Syria’s defense ministry said on Thursday that one of its soldiers has been killed and three injured in an overnight Israeli airstrike on a telecommunication tower in the central province of Homs.

A military official said the strike shortly before midnight in the Palmyra region hit the tower and some posts around it. The official did not identify the targets further. Syrian air defenses were activated to respond to the incoming missiles, which the defense ministry said originated from the Tanf region in southeast Syria.

In a rare acknowledgement their bases had been struck, Iran-backed groups in Syria vowed retaliation. The groups said they will “have a harsh response” to the Israeli strikes in Palmyra.

The groups also blamed the United States for the strikes, which originated from Tanf, where the U.S. has a small outpost in the area that straddles the Baghdad-Damascus highway.

The groups said the strikes hit service and youth centers, causing a number of causalities, between dead and wounded. The groups did not provide details.

The Britain-based Syrian Observatory for Human Rights, a war monitor, said the strikes hit an airbase known as T4, adding that Iran-backed militiamen based in it were targeted.

Israel has staged hundreds of strikes against Iran-linked military targets in government-controlled Syria over the years but rarely acknowledges or discusses such operations.

Recently, there has been an intensification of such strikes, with the last being on Friday in the same area, wounding six soldiers.

Israel sees the Iranian presence on its northern frontier as a red line, and it has repeatedly struck what it has described as Iran-linked facilities and weapons convoys destined for Lebanon’s militant Hezbollah group.

Associated Press