PALM BEACH, Fla. (AP) — The United States blasted a Syrian air base with a barrage of cruise missiles Thursday night in fiery retaliation for this week’s gruesome chemical weapons attack against civilians.

President Donald Trump cast the U.S. assault as vital to deter future use of poison gas and called on other nations to join in seeking “to end the slaughter and bloodshed in Syria.”

It was the first direct American assault on the Syrian government and Trump’s most dramatic military order since becoming president just over two months ago.

Announcing the assault from his Florida resort, Trump said there was no doubt Syrian President Bashar Assad was responsible for the chemical attack, which he said employed banned gases and killed dozens.

“Assad choked out the lives of innocent men, women and children,” Trump declared.

Watch Trump’s response via video in the media player top of this report.

The U.S. strikes hit the government-controlled Shayrat air base in central Syria, where U.S. officials say the Syrian military planes that dropped the chemicals had taken off.

The U.S. missiles hit at 8:45 p.m. in Washington, 3:45 a.m. Friday morning in Syria. The missiles targeted the base’s airstrips, hangars, control tower and ammunition areas, officials said.

“While tonight’s military action against Syria won’t remove Assad from power nor solve the horrifying humanitarian disaster, destroying the airfield will damage Assad’s ability to launch attacks against his own people,” Rep. Chris Stewart, R-Utah, said in a statement issued Thursday. “It also sends a very clear message that the U.S. will no longer tolerate Assad’s use of chemical weapons against his own people. Other tyrants around the world are surely taking note as well.”

Syrian state TV reported a U.S. missile attack on a number of military targets and called the attack an “aggression.”

The surprise U.S. assault marked a striking reversal for Trump, who warned as a candidate against the U.S. getting pulled into the Syrian civil war, now in its seventh year. But the president earlier in the week appeared moved by the photos of children killed in the chemical attack, calling it a “disgrace to humanity” that crossed “a lot of lines.”

About 60 U.S. Tomahawk missiles, fired from warships in the Mediterranean Sea, targeted an air base in retaliation for a chemical weapons attack that American officials believe Syrian government aircraft launched with a nerve agent, possibly sarin.

“Like all Americans, I was shocked and saddened by the images of chemical weapons used in Syria this week. The use of indiscriminate and inhumane tactics like this, especially against non-combatants, should be condemned in the strongest terms,” Sen. Mike Lee, R-Utah, stated Thursday evening. “President Trump should make his case in front of the American people and allow their elected representatives to debate the benefits and risks of further Middle East intervention to our national security interests.”

“If the United States is to increase our use of military force in Syria, we should follow the Constitution and seek the proper authorization from Congress,” Lee said. “I stand ready to stay in Washington, or come back to Washington, in order to properly consider any further military action and the national security interests of the American people.”

The president did not announce the attacks in advance, though he and other national security officials ratcheted up their warnings to the Syrian government throughout the day Thursday.

“I think what happened in Syria is one of the truly egregious crimes and shouldn’t have happened and it shouldn’t be allowed to happen,” Trump told reporters traveling on Air Force One to Florida, where he was holding a two-day summit with Chinese President Xi Jinping.

The strike came as Trump was hosting Xi in meetings focused in part on another pressing U.S. security dilemma: North Korea’s nuclear program. Trump’s actions in Syria could signal to China that the new president isn’t afraid of unilateral military steps. even if key nations like China are standing in the way.

Before the strikes, U.S. military officials said they informed their Russian counterparts of the impending attack. The goal was to avoid any accident involving Russian forces.

Nevertheless, Russia’s Deputy U.N. ambassador Vladimir Safronkov warned that any negative consequences from the strikes would be on the “shoulders of those who initiated such a doubtful and tragic enterprise.”

The U.S. also notified its partner countries in the region prior to launching the strikes.

Trump’s decision to attack Syria came 3 1/2 years after President Barack Obama threatened Assad with military action after an earlier chemical weapons attack killed hundreds outside of Damascus. Obama had declared the use of such weapons a “red line.”

At the time, several American ships in the Mediterranean were poised to launch missiles, only for Obama to abruptly pull back after key U.S. ally Britain and the U.S. Congress balked at his plan.

He opted instead for a Russian-backed plan that was supposed to remove and eliminate Syria’s chemical weapons stockpiles.

The world learned of the chemical attack earlier in the week in footage that showed people dying in the streets and bodies of children stacked in piles.

Written by JULIE PACE, Associated Press, VIVIAN SALAMA, Associated Press, LOLITA C. BALDOR, Associated Press