(Fox News) President Trump on Friday announced that he has approved military strikes in Syria against the regime of Syrian President Bashar al-Assad.

The decision follows a suspected chemical gas attack from the Assad regime on a rebel-held town near the Syrian capital last weekend.

The United States launched the response, along with assurance from France and the United Kingdom, Trump stated.

French President Emmanuel Macron said the operation is currently targeting the “clandestine chemical arsenal” in Syria.

“This evening I have authorized British armed forces to conduct coordinated and targeted strikes to degrade the Syrian Regime’s chemical weapons capability and deter their use,” British Prime Minister Theresa May said in a statement.

Trump’s announcement immediately preceded reports of loud explosions lighting up the sky in Damascus. Syrian TV reported that Syrian air defenses have responded to the U.S.-British-French attack.

Trump said the U.S. is prepared to “sustain” pressure on Assad until he ends what the president called a criminal pattern of killing his own people with internationally banned chemical weapons. It wasn’t immediately clear whether Trump meant the allied military operation would extend beyond the initial nighttime round of missile strikes.

At least 40 people died in the chemical attack in Douma last Saturday, about 10 miles east of Damascus, and over 500 people, mostly women and children, were injured and brought to medical centers. The attack occurred amid a resumed offensive by Syrian government forces after the collapse of a truce. Syrian activists, rescuers and medics said families suffocated in their homes.

Assad’s actions, Trump said, “are not the actions of a man,” but “are the crimes of a monster instead.”

A similar chemical attack in Khan Sheikhoun in April 2017 that killed nearly 100 people prompted the U.S. to launch dozens of cruise missiles at a Syrian airfield to dissuade Assad from using chemical weapons in the future, officials said. But during the weekend, images of dead and sick women and children again circulated following another alleged chemical attack.

In his statement, the president also hit Russia and Iran for their sustained support of the Assad regime.

“To Iran and to Russia I ask, what kind of nation wants to be associated with the mass murder of innocent men, women and children,” Trump said.

“The nations of the world can be judged by the friends that they keep,” he continued. “Russia must decide if it will continue down this dark path or continue with civilized nations.

“The nations of the world can be judged by the friends they keep. Hopefully someday we’ll get along with Russia, and maybe even Iran, but maybe not.”

This is a developing story; please check back for updates

Fox News’ Ben Evansky, Alex Pappas and The Associated Press contributed to this report.