Unknown aircraft Saturday attacked positions of Iran-backed forces in and around Syria’s eastern city of Deir ez-Zor for the second time this week.

The Syrian Observatory for Human Rights (SOHR) said, “Several explosions took place on Saturday in Deir ez-Zor city and its vicinity which are under the control of the regime and Iranian-affiliated militia."

Unidentified warplanes carried out airstrikes against targets in Hawijah Kate and a nearby bridge in the northern part of Deir ez-Zor city, the SOHR said.

Israel frequently targets forces under Iranian command in Syria to prevent the Islamic Republic from accumulating weapons and entrenching itself further in the war-torn country.

Al-Arabiya, however, quoted sources as saying that American drones had launched the attack.

Israel’s military does not usually comment on specific strikes in Syria but has acknowledged that it has conducted hundreds of attacks against Iran-backed groups. It has also claimed several attacks on arms shipments believed to be bound for Hezbollah forces or other Iran-linked groups there.

Last month, Israel allegedly carried out three strikes in Syria.

According to Syrian state media, the latest attack was on April 27, when surface-to-surface missiles were fired from northern Israel at military positions near capital Damascus, killing four Syrian soldiers and injuring three others.

In March, an Israeli attack over the Syrian capital Damascus killed two officers from Iran’s Revolutionary Guard and left some material damage.