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.

Read more of this story at Military.com.