WASHINGTON — U.S. and allied attacks on three suspected Syrian chemical and biological weapons facilities degraded President Bashar Assad’s ability to produce deadly gas and nerve agents, Pentagon officials said Saturday, hours after warships and planes fired a barrage of about 120 missiles.

The coordinated strike by the United States, France and the United Kingdom was carried out “to cripple Syria’s ability to use chemical weapons in the future,” Pentagon spokeswoman Dana White said.

“It was a deliberate decision to go to the storage facilities, to go to the research facilities,” she said. “We’re confident that we’ve significantly degraded his ability ever to use chemical weapons again.”

Pentagon officials said initial reports indicated that every missile struck its target. It said no warplanes or missiles were shot down by Syrian or Russian air defense systems, despite claims from officials in those countries that they had intercepted dozens of incoming missiles.

The Pentagon has received no reports of civilian casualties from the strikes, officials said.

Syria and its allies, including Russia and Iran, made no attempt to retaliate against the 2,000 U.S. troops deployed in northeast Syria.

Pentagon officials had worried that the predawn attack could escalate into a wider conflict, deepening U.S. involvement in Syria only weeks after President Donald Trump said the U.S. would withdraw from the country.

But the limited missile strikes left many questions unanswered, including whether Syria had been able to protect its chemical-weapons stockpiles because Trump had telegraphed that a strike was coming in a series of taunting Twitter posts over the past week.

Marine Lt. Gen. Kenneth F. McKenzie, director of the Pentagon’s Joint Staff, which helped plan the attack, said Syria may have been able to remove materials from the three targeted facilities _ one near Damascus and two around the city of Homs.

But it would not have been possible to remove all the key equipment and chemicals, McKenzie said.

“I believe that there was materiel and equipment associated with each of these sites that was not movable, and that’s what really sets them back,” he said.

All the coalition missiles were fired from warplanes or ships in the Red Sea, Persian Gulf and eastern Mediterranean Sea, hundreds of miles from their targets.

The missiles arrived almost simultaneously, hitting within minutes of 4 a.m. local time in Syria, officials said.

The strategy of avoiding Syrian airspace and firing from multiple directions simultaneously was designed to confuse and overwhelm Syrian and Russian air defense systems.

Syria launched up to 40 air defense missiles, but only after all the incoming U.S., French and British weapons had already struck, McKenzie said.

“The Syrian response was remarkably ineffective,” McKenzie said. Russia fired no missiles, he said.

A suspected gas attack April 7 killed at least 43 people as troops loyal to the government pressed an offensive to take Douma, a rebel-held bastion near the Syrian capital. The area was later captured by troops loyal to Assad.

U.S. officials say intelligence information and forensic samples obtained from victims indicate that Syria used chlorine gas in the attack. Evidence also suggests that sarin, a banned nerve agent, was mixed in, officials said, but that has not been confirmed.

Trump ordered a similar strike last April. Warships fired 59 Tomahawk cruise missiles fired at a Syrian airfield after a sarin attack. In that case, officials said, there was clear evidence that Syria had used sarin.

In ordering the most recent strikes, the Trump administration and its allies appeared to be drawing a new line, suggesting that using even chlorine gas would spark military reprisals.

Pentagon officials refused to say how they would respond if another deadly chlorine attack occurred, though they explicitly warned Moscow to restrain Assad and force him to live up to pledges to give up his chemical-weapons stockpile completely.

“What happens next has everything to do with what the Assad regime decides to do, and it has everything to do with what the Russian government decides to enable,” White said.

Pentagon officials worried that attacking chemical-weapons storage facilities might cause the accidental release of deadly gas. But use of highly accurate Tomahawk missiles helped mitigate that danger by striking the facilities in ways that lowered chances of an accidental release, McKenzie said.

There were no reports of gas being accidentally released, he said.

The largest and most important of the targets struck was the Barzah Research and Development Center near Damascus, which officials described as a key facility in the Syrian chemical and biological weapons program.

It was leveled by 57 cruise missiles and 19 long-range air-to-ground attack missiles fired from U.S. Navy vessels and submarines and Air Force B-1 bombers in Persian Gulf, officials said.

Before-and-after pictures released by the Pentagon show the attack collapsed three buildings and a parking garage at the site.

“They had three buildings there and a parking deck, and now they don’t,” said McKenzie.

Britain’s attacks were focused on the Him-Shinshar chemical storage facility, west of the city of Homs. The British fired eight long-range air-to-ground missiles from Tornado and Typhoon fighters. The U.S. and French also hit the facility with multiple missiles.

“Our initial assessment is that this target was completely destroyed, “McKenzie said.

France targeted a nearby storage bunker where chemical and biological weapons were kept, hitting it with seven cruise missiles. McKenzie said the facility had been “successfully hit and sustained damage.”