A U.S. official described it as “a large-scale” strike that hit 70 targets in areas across central Syria that had IS infrastructure and weapons. Another U.S. official, who also spoke on condition of anonymity to discuss sensitive operations, said more strikes should be expected.

“This is not the beginning of a war — it is a declaration of vengeance. The United States of America, under President Trump’s leadership, will never hesitate and never relent to defend our people,” Defense Secretary Pete Hegseth said on social media.

The new military operation in Syria comes even as the Trump administration has said it’s looking to focus closer to home in the Western Hemisphere, building up an armada in the Caribbean Sea as it targets alleged drug-smuggling boats and vowing to keep seizing sanctioned oil tankers as part of a pressure campaign on Venezuela’s leader. The U.S. has shifted significant resources away from the Middle East to further those goals: Its most advanced aircraft carrier arrived in South American waters last month from the Mediterranean Sea.

Trump vowed retaliation

President Donald Trump pledged “very serious retaliation” after the shooting in the Syrian desert, for which he blamed IS. Those killed were among hundreds of U.S. troops deployed in eastern Syria as part of a coalition fighting the militant group.

During a speech in North Carolina on Friday evening, the president hailed the operation as a “massive strike” that took out the “ISIS thugs in Syria who were trying to regroup.”

Earlier, in his social media post, he reiterated his backing for Syrian President Ahmad al-Sharaa, who Trump said was “fully in support” of the U.S. effort.

Trump also offered an all-caps threat, warning IS against attacking American personnel again.

“All terrorists who are evil enough to attack Americans are hereby warned — YOU WILL BE HIT HARDER THAN YOU HAVE EVER BEEN HIT BEFORE IF YOU, IN ANY WAY, ATTACK OR THREATEN THE U.S.A.,” the president added.

The attack was conducted using F-15 Eagle jets, A-10 Thunderbolt ground attack aircraft and AH-64 Apache helicopters, the U.S. officials said. F-16 fighter jets from Jordan and HIMARS rocket artillery also were used, one official added.

U.S. Central Command, which oversees the region, said in a social media post that American jets, helicopters and artillery employed more than 100 precision munitions on Syrian targets.

How Syria has responded

The attack was a major test for the warming ties between the United States and Syria since the ouster of autocratic leader Bashar Assad a year ago. Trump has stressed that Syria was fighting alongside U.S. troops and said al-Sharaa was “extremely angry and disturbed by this attack,” which came as the U.S. military is expanding its cooperationwith Syrian security forces.

Syria’s foreign ministry in a statement on X following the launch of U.S. strikes said that last week’s attack “underscores the urgent necessity of strengthening international cooperation to combat terrorism in all its forms” and that Syria is committed “to fighting ISIS and ensuring that it has no safe havens on Syrian territory and will continue to intensify military operations against it wherever it poses a threat.”

Syrian state television reported that the U.S. strikes hit targets in rural areas of Deir ez-Zor and Raqqa provinces and in the Jabal al-Amour area near the historic city of Palmyra. It said they targeted “weapons storage sites and headquarters used by ISIS as launching points for its operations in the region.”

IS has not said it carried out the attack on the U.S. service members, but the group has claimed responsibility for two attacks on Syrian security forces since, one of which killed four Syrian soldiers in Idlib province. The group in its statements described al-Sharaa’s government and army as “apostates.” While al-Sharaa once led a group affiliated with al-Qaida, he has had a long-running enmity with IS.

The Americans who were killed

Trump this week met privately with the families of the slain Americans at Dover Air Force Base in Delaware before he joined top military officials and other dignitaries on the tarmac for the dignified transfer, a solemn and largely silent ritual honoring U.S. service members killed in action.

The guardsmen killed in Syria last Saturday were Sgt. Edgar Brian Torres-Tovar, 25, of Des Moines, and Sgt. William Nathaniel Howard, 29, of Marshalltown. Ayad Mansoor Sakat, of Macomb, Michigan, a U.S. civilian working as an interpreter, also was killed.

The shooting near Palmyra also wounded three other U.S. troops as well as members of Syria’s security forces, and the gunman was killed. The assailant had joined Syria’s internal security forces as a base security guard two months ago and recently was reassigned because of suspicions that he might be affiliated with IS, Interior Ministry spokesperson Nour al-Din al-Baba has said.

The man stormed a meeting between U.S. and Syrian security officials who were having lunch together and opened fire after clashing with Syrian guards.