Iran’s Islamic Revolutionary Guard Corps (IRGC) says four of its “military advisers” have been killed in an Israeli air strike on a residential building in Syria’s capital, Damascus.

Syrian state media SANA said the attack on Saturday took place in the Mazzeh neighbourhood. It said “Israeli aggression” targeted the building.

A well-informed source told Al Jazeera the target was an IRGC intelligence unit, adding that a senior IRGC intelligence official in Syria and his assistants were in the building.

In a brief statement, the IRGC said an air strike by Israeli fighter jets killed “a number of Syrian forces and four military advisers”, without mentioning their names or their titles. Iranian state television called it a “terrorist” attack by Israel.

Iranian state media reported the attack, which is believed to have been carried out with at least four missiles.

The strikes completely destroyed a four-storey building and at least one person was taken to hospital, but more casualties could be found once the rubble has been cleared, reports said.

There was no immediate comment from Israel.

The Syrian Observatory for Human Rights, a Britain-based monitor that relies on a network of sources on the ground, said the attack killed five people in a building where “Iran-aligned leaders” were meeting.

“An Israeli missile strike targeted a four-storey building, killing five people … and destroying the whole building where Iran-aligned leaders were meeting,” said the Syrian Observatory.