On President Donald Trump's order, two Navy destroyers in the eastern Mediterranean Sea fired salvos of Tomahawk cruise missiles at a Syrian airfield that U.S. intelligence cited as the source of the deadly chemical attack on civilians earlier this week.

The destroyers Ross and Porter together around 4:40 a.m. Friday local time fired 59 BGM-109 Tomahawk missiles, each with 1,000-pound conventional warheads and costing about $1 million, at the Shayrat base north of Damascus. The attack was quick, lasting only a couple of minutes.

"The intent was to deter the regime from doing this again," said Navy Capt. Jeff Davis, a Pentagon spokesman, referring to the suspected nerve agent attack by a Syrian air force warplane on Tuesday against the town of Khan Sheikhoun in northwestern Syria's Idlib governorate.

Human rights and aid groups charged that more than 70 were killed and hundreds injured in the attack allegedly ordered by Syrian President Bashar al-Assad. Photos and videos of the alleged Sarin gas attack circulated on social media.

Of the Shayrat airbase targeted in the U.S. strike, Davis said, "This was a place prior to 2013 that was one of their main chemical weapons storage sites -- a lot of those sites were dismantled at the time as they were seeking to comply, but they were obviously using it again."

The cruise missile strike marked the first U.S. military action against the Assad regime, which has been supported by Russia.

"Assad choked out the lives of helpless men, women and children ... No child of God should ever suffer such horror," Trump said in a statement. "Tonight, I ordered a targeted military strike in Syria from where the chemical attack was launched. It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons."

The president added that the U.S. had no choice since years of "previous attempts at changing Assad's behavior have all … failed very dramatically."

Davis said Russian personnel at the Shayrat airfield were warned several times before the strikes began at 8:40 p.m. Eastern time and lasted only a few minutes. The barrage of cruise missiles also was aimed to avoid an area where Russian personnel were based, he said.

"There were multiple conversations with the Russians" before the missiles were launched through a communications channel set up by the U.S. military and the Russian Defense Ministry in Latakia to avoid air mishaps, Davis said. No direct contacts were made to Moscow, he said.

The Tomahawk Land Attack Missiles, or TLAMs, targeted Syrian aircraft, hardened shelters, fuel and logistics depots, ammunition storage bunkers and air defense radars, Davis said. A detailed bomb damage assessment was underway but the spokesman said the initial estimate was that the strikes "severely damaged Syrian aircraft."

Davis could give no estimate on possible Syrian or Russian casualties from the strikes, but said the targeting sought to avoid personnel and no Russians were believed to be killed in the attack. Russian troops had reportedly served at the location in the past.

Syria said six people were killed in the strike, according to CNN.

Davis declined to disclose the surveillance techniques the U.S. employed to determine the that Shayrat airfield was the source of the chemical attack, but he said that U.S. intelligence tracked the Syrian warplane, believed to be a Sukhoi-22 "Fitter," a Soviet-era fighter-bomber that dropped the munitions containing the deadly agents.

Trump, who was meeting Thursday with Chinese President Xi Jinping at the U.S. president's estate in Mar-a-Lago in Palm Beach, Florida, gave the order after a briefing earlier in the day with Defense Secretary James Mattis and National Security Adviser Army Lt. Gen. H.R. McMaster.

Presented with several military options, Trump indicated that he was about to authorize action that could mire the U.S. even deeper in the endless conflicts of the Mideast.

"I don't want to say what I'm going to be doing with respect to Syria," the president said aboard Air Force One on his way to Florida. Yet he singled out Assad for blame in Tuesday's attack.

"What Assad did is terrible. What happened in Syria is truly one of the egregious crimes and it shouldn't have happened and it shouldn't be allowed to happen," the president said. "I think what happened in Syria is a disgrace to humanity, and he's there, and I guess he's running things, so I guess something should happen."

There was no immediate response to the U.S. action by Russian President Vladimir Putin, whose forces have propped up the Assad regime since 2014, when Moscow's troops and warplanes entered Syria. Russian officials had called on Trump to exercise patience.

Kremlin spokesman Dmitry Peskov warned Thursday against "snap judgments" on what happened in Idlib.

"It's indeed a very menacing course of events, a dangerous and horrible crime," he said of the chemical attack. "However, sticking labels on everyone, prematurely, is not a correct thing to do, in our opinion."

The Russian Foreign Ministry added that it was "premature to accuse the Syrian government of using chemical weapons in Idlib."

Both Moscow and Damascus have made similar arguments that the release of the suspected nerve agent may have been caused by an airstrike that hit a munitions depot where rebel groups were storing chemicals.

Trump was already being pressed by senior Republicans to take military action.

Sen. John McCain, an Arizona Republican and chairman of the Senate Armed Services Committee, and Sen. Lindsey Graham, a South Carolina Republican and member of the panel, said the U.S. and its partners should ground Assad's warplanes, though any attack on Syrian airfields would also risk hitting Russian aircraft and crews.

"The U.S. military, together with our allies and partners, has the capability to achieve this objective quickly, precisely, decisively, and in ways that control escalation," McCain said in a statement. He did not elaborate on the method of attack.

In 2013, following a sarin gas attack in the Damascus suburbs that allegedly killed more than 1,500, the U.S. posted destroyers and submarines to the eastern Mediterranean with the potential mission to fire Tomahawk cruise missiles to crater Syrian airfields and eliminate air defenses, but the attack order never came from the Obama administration.

The strikes in Syria were the second military action personally authorized by Trump since his inauguration. In January, he signed off on the Special Operations raid in Yemen in which Senior Chief Petty Officer William "Ryan" Owens, a member of Navy SEAL Team 6, was killed, several other members of the raid team were wounded, and a $70 million MV-22 Osprey tilt-rotor aircraft had to be destroyed.

The latest U.S. action marks a new chapter in the six-year-old Syrian civil war which has killed more than 400,000, displaced 10 million and sent streams of desperate refugees to Europe where their presence has sparked political turmoil.

U.S. policy had been that military action in Syria and in Iraq was limited to the fight against the Islamic State of Iraq and Syria, or ISIS, and the Obama administration maintained that position when Putin ordered his forces into Syria in 2014 as Assad's downfall seemed imminent.

The Trump administration last week signaled a major shift in the long-standing policy of the Obama administration that Assad had to step down eventually as part of any peace settlement. Secretary of State Rex Tillerson said that the U.S. was taking a more neutral position. Assad's fate should be decided by the Syrian people, he said.

Tillerson appeared to reverse course Thursday, saying that Assad should have "no role" in Syria's future and adding that the suspected nerve agent attack deserved a "serious response" by the U.S. and its allies.

"We are considering an appropriate response for this chemical weapons attack," Tillerson said at Trump's Florida estate, where he was joining Trump for talks with Chinese President Xi Jinping. "A serious matter requires a serious response."

The strikes followed a round of top-level consultations involving White House officials, including Mattis and Joint Chiefs Chairman Joseph Dunford on various military options to punish Assad while avoiding a wider conflict with Russia, whose forces are closely integrated those of the regime. Mattis was with Trump at Mar-a-Lago Thursday when he made the decision.

The stage for the strikes was set on Wednesday in the White House Rose Garden where Trump, at a joint news conference with Jordan's King Abdullah, lashed out at Assad for the chemical attack and strongly suggested that he was considering retaliation.

The scenes from northwestern Syria of the dead and writhing victims struggling to breathe "crossed a lot of lines for me," said Trump in series of remarks that appeared to make it difficult him not to act without losing face.

In Turkey, where many of the victims were taken for treatment, the Turkish Health Ministry said in a statement Thursday that the chemical used in the attacks was the deadly and banned nerve agent sarin.

"According to the results of preliminary tests, patients were exposed to chemical material (Sarin)," the statement said.

White House Press Secretary Sean Spicer indicated that the strikes could be the first step in an overall U.S. plan to set up so-called "safe zones" in northern Syria for refugees that would be policed and defended by U.S. troops. Trump often spoke favorably of the safe zone concept during the election campaign.

Spicer said Trump's top priority was the security of the American people but "that doesn't mean we can't support efforts like safe zones throughout Syria."

The Obama administration prepared plans to strike Syrian targets with sea-launched cruise missiles after an August 2013 Syrian chemical weapons attack that killed more than 1,400 civilians, including hundreds of children.

Those plans were shelved when Mr. Obama decided instead to negotiate an agreement with the Russians to eliminate Syria's declared chemical weapons arsenal and the equipment to make poison gas. The chemical agents were destroyed at sea but rebel groups charged that Assad retained secret stockpiles.

Since then, human rights groups have charged that the Syrian regime has launched several attacks with chlorine gas.

Trump's decision to launch the strikes marked a "significant shift in policy" that will alter the course of U.S. involvement and commitment to the region in ways that are not immediately clear, a defense official told Military.com at the Pentagon.

"Think about what changes here," the official said. "The policy thus far has been to look at ISIS," said the official, who spoke on grounds of anonymity. Now, the U.S., leader of the anti-ISIS coalition, would be in conflict with the terror group and the Assad regime. "Your resources are now split," the official said. "You're potentially at war with Syria."

The troubling question now was how Assad -- and Putin -- respond to the U.S. offensive and change in policy, the official said. He asked: "How would you make this a limited strike – all while fighting ISIS? What would the Russians response be?"

Tillerson was expected to meet in Moscow next week with Putin on a previously arranged visit that will now have Syria high on the agenda.

The talks will come as Trump's high hopes, often expressed during the campaign, for a new and more cooperative relationship with Putin appeared to have been dashed by charges of Russian meddling in the U.S. 2016 elections and congressional investigations of possible collusion between Trump associates and Moscow.

The Force Management Levels, or limits, on U.S. military personnel set by the Obama administration currently stand at 503 for Syria and 5,262 Iraq. However, those numbers do not include troops on so-called "temporary assignment."

Currently in Syria, a small contingent of Army Rangers and Stryker combat vehicles is in the northeastern town of Manbij temporarily to discourage any attempt to take the town by a combined Syrian and Russian force on the outskirts. In addition, about 200 Marines from the 11th Marine Expeditionary Unit, also on temporary assignment, are near the ISIS stronghold of Raqqa to set up a firing base for M777 howitzers.

In Iraq, about 200 troops from the Army's 82nd Airborne Division recently were sent to northeastern Iraq to support the train, advise and assist mission of U.S. troops with the Iraqi Security Forces battling to retake Mosul.

In fielding questions Thursday on the possible repercussions for U.S. troops on the ground in Syria, a U.S. military spokesman said that the troops have ready access to chemical weapons protective suits but were not wearing them as a precaution following the suspected Syrian air force nerve gas attack.

"All forces have access to chemical gear" in Syria and in Iraq, Army Col. Joseph Scrocca said but "None of our forces currently are wearing them."

Scrocca, a spokesman for Combined Joint Task Force-Operation Inherent Resolve, declined comment on the alleged Syrian attack or a possible U.S. response. He said U. S. troops in Syria and Iraq were focused on the fight against ISIS but "our forces across Iraq and Syria are prepared to defend themselves" should they come under fire.

When asked if the U.S. cruise missile strike into Syria would be limited in nature, Davis, the Pentagon spokesman, said, "we hope so."

-- Richard Sisk
-- Oriana Pawlyk

Military.com