Damascus/Tehran, Jan 21 : Four officers of Iran's Islamic Revolutionary Guard Corps (IRGC) and an unknown number of civilians were killed in an Israeli missile attack on a residential neighbourhood in the Syrian capital of Damascus, an Iranian media source said. The source, who requested anonymity, said a two-storey building, the second floor of which was occupied by a unit associated with the IRGC, was attacked by at least four missiles. In addition to the four IRGC members who lost their lives, there have reportedly been casualties among the civilians in the same building, he said, adding rescue missions were underway to find bodies under the rubble. A local eyewitness told Xinhua that a Palestinian family was living on the ground floor of the building. It is believed that all of them were now buried under the rubble, as none of them were seen after the attack, he noted. According to a statement released by the Syrian army, Israel carried out the airstrike from the occupied Syrian Golan Heights at 10:20 a.m. local time, Xinhua news agency reported. It said the airstrike resulted in the death and injury of a number of civilians, the complete destruction of the targetted building, and caused damage to neighbouring structures. Iran's semi-official Mehr news agency reported that four IRGC members, including two high-ranking advisers, were killed in the Israeli attack on Saturday. According to Mehr, the head of the IRGC's advisory intelligence in Syria and his deputy, along with two other members of the elite force, were killed. Right after the attack, another eyewitness living in the area told Xinhua he heard four to six missiles passing through the sky in quick succession. The witness noted that the sound was relatively soft, akin to a whizzing noise. Shortly after hearing the missiles, the witness observed white smoke rising from an area near the Muhammady Mosque in the Western Villas of Mazzeh. Meanwhile, the Britain-based Syrian Observatory for Human Rights, a war monitor, said it had confirmed six deaths, including one Syrian civilian, three IRGC members, and two others whose nationality remained unknown. It noted that the Israeli attack targetted IRGC leaders who were present at a meeting. The Iranian news outlet Jadeh Iran said the attack may have been a response to the IRGC's activities, particularly its attack on a base of Israel's intelligence agency Mossad in Erbil in northern Iraq on January 15. The latest strike is part of the ongoing escalation of tensions between Iran and Israel. Israel has intensified its assaults on Iranian targets in Syria, prompting pro-Iran militias in Syria to retaliate by targetting US interests. In a report published on Saturday, the Observatory warned that the escalating tensions may potentially drag the region into a wider confrontation between Iran and Israel on Syrian soil. /IANS