DAMASCUS, Syria>> Jordan confirmed Saturday that its air force took part in strikes launched by the United States on Islamic State targets in Syria in retaliation for the killing of three U.S. citizens this month.

The U.S. launched military strikes Friday on multiple sites in Syria to “eliminate” Islamic State fighters and weapons in retaliation for an attack by a Syrian gunman that killed two U.S. troops and an American civilian interpreter almost a week earlier.

The Jordanian military said in a statement that its air force “participated in precise airstrikes ... targeting several (Islamic State) positions in southern Syria,” using a different abbreviation for the Islamic State. Jordan is one of 90 countries making up the global coalition against the Islamic State. Syria recently joined the coalition.

The U.S. military did not say how many had been killed in Friday’s strikes. The Syrian Observatory for Human Rights, a U.K.-based war monitor, reported that at least five people were killed, including the leader and members of an Islamic State cell.

The Jordanian statement said the operation aimed “to prevent extremist groups from exploiting these areas as launching pads to threaten the security of Syria’s neighbors and the wider region, especially after (the Islamic State) regrouped and rebuilt its capabilities in southern Syria.”

U.S. Central Command, which oversees the region, said in a statement that its forces “struck more than 70 targets at locations across central Syria with fighter jets, attack helicopters and artillery,” with the Jordanian air force supporting with fighter aircraft.

It said that since the Dec. 13 attack in Syria, “U.S. and partner forces conducted 10 operations in Syria and Iraq resulting in the deaths or detention of 23 terrorist operatives,” adding that the U.S. and partners have conducted more than 80 counterterrorism operations in Syria in the past six months.

President Donald Trump had pledged “very serious retaliation” after the shooting in the Syrian desert, for which he blamed the Islamic State. Those killed were among hundreds of U.S. troops deployed in eastern Syria as part of a coalition fighting the militant group. On Friday, Trump reiterated his backing for Syrian interim President Ahmad al-Sharaa, who Trump said was “fully in support” of the U.S. strikes against the Islamic State.

The Islamic State has not taken responsibility for the attack on the U.S. service members, but the group has claimed 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.”

Al-Sharaa has had a long-running enmity with the Islamic State.

As well as killing three U.S. citizens, the shooting near Palmyra also wounded three U.S. troops as well as members of Syria’s security forces, and the gunman was killed.