WASHINGTON >> The United States and European allies launched airstrikes early today against Syrian research, storage and military targets as President Donald Trump sought to punish President Bashar Assad for a suspected chemical attack near Damascus last weekend that killed more than 40 people.

Britain and France joined the United States in the strikes in a coordinated operation intended to show Western resolve in the face of what the leaders of the three nations called persistent violations of international law. Trump characterized it as the beginning of a sustained effort to force Assad to stop using banned weapons but ordered only a limited one-night operation that hit three targets.

“These are not the actions of a man,” Trump said of last weekend’s attack in a televised address from the White House Diplomatic Room. “They are crimes of a monster instead.”

While he has talked as recently as last week about pulling U.S. troops out of Syria, the president vowed to remain committed to the goal of preventing further attacks with deadly poisons. “We are prepared to sustain this response until the Syrian regime stops its use of prohibited chemical agents,” Trump said.

But Defense Secretary Jim Mattis, who had urged caution in White House deliberations leading up to the strike, told reporters Friday night that there would be no more attacks unless Assad again used gas on his own people.

“We confined it to the chemical weapons-type targets,” Mattis said. “We were not out to expand this; we were very precise and proportionate. But at the same time it was a heavy strike.”

The assault was twice the size and hit two more targets than a strike Trump ordered last year against a Syrian military airfield. Launched from warplanes and naval destroyers, the burst of missiles and bombs struck Syria shortly after 4 a.m. local time today.

They hit three of Assad’s chemical weapons facilities: a scientific research center in greater Damascus that was used for production of weapons, and two chemical weapons facilities west of Homs — one used for the production of the nerve agent sarin and the other a part of a military command post, said Gen. Joseph F. Dunford Jr., chairman of the Joint Chiefs of Staff.

Residents of Damascus, the capital, woke to the sounds of multiple explosions shaking the city before the dawn call to prayer. The city and the hills are surrounded by military facilities, and it appeared that these were among the targets.

Syrian state television said government air defense systems were responding to “the American aggression” and aired video of missiles being fired into a dark night sky. It was not clear whether they hit anything. It reported that 13 missiles had been shot down by Syrian air defenses near Al-Kiswa, a town south of Damascus. U.S. officials said they could not yet confirm that.

A complex war

The strikes risked pulling the United States deeper into the complex, multisided war in Syria from which Trump only last week said he wanted to withdraw. They also raised the possibility of confrontation with Russia and Iran, both of which have military forces in Syria to support Assad.

Trump called on Syria’s patrons in Russia and Iran to force Assad to halt the use of poison gas in the seven-year civil war that has wracked his country.

“To Iran and to Russia I ask, What kind of a nation wants to be associated with the mass murder of innocent men, women and children?” he said. “The nations of the world can be judged by the friends they keep. No nation can succeed in the long run by promoting rogue states, brutal tyrants and murderous dictators.”

Russia responded with sharp words. “We warned that such actions will not be left without consequences,” Anatoly Antonov, ambassador to the United States, said in a statement. “All responsibility for them rests with Washington, London and Paris.”

Taking umbrage at Trump’s accusing President Vladimir Putin in his speech of not living up to a promise to disarm Syria of its chemical weapons, Antonov added, “Insulting the president of Russia is unacceptable and inadmissible.”

Limited strike

In choosing to strike, it appeared that Trump’s desire to punish Assad for what he called a “barbaric act” — and make good on his tweets promising action this week — outweighed his desire to limit the U.S. military involvement in the conflict, at least in the short term.

The strikes marked the second time Trump has attacked Syria to punish the government after it was accused of using chemical weapons. The White House had sought to create a response that would be more robust than the attack in April 2017, when the United States fired 59 Tomahawk cruise missiles at a Syrian air base that was back in use a day later.

Unlike last year, France and Britain joined the United States in retaliating for the suspected chemical attack in the town of Douma, outside Damascus, on April 7, but Germany refused to take part, even though Chancellor Angela Merkel called the use of chemical weapons “unacceptable.”

Prime Minister Theresa May of Britain said Syria had left the allies no choice. “This persistent pattern of behavior must be stopped — not just to protect innocent people in Syria from the horrific deaths and casualties caused by chemical weapons, but also because we cannot allow the erosion of the international norm that prevents the use of these weapons,” she said.

But she also emphasized the limits of the operation’s goals, reflecting the reluctance in London as well as Washington to become too immersed in the fratricidal war in Syria.

“This is not about intervening in a civil war,” she said. “It is not about regime change. It is about a limited and targeted strike that does not further escalate tensions in the region and that does everything possible to prevent civilian casualties.”

Defense officials said Tomahawk cruise missiles were launched from three U.S. warships, while B-1 bombers dropped long-range missiles on targets. French and British warplanes also fired long-range missiles, while a British submarine launched cruise missiles.

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