UN Secretary-General Ban Ki-moon on Thursday noted with "grave concern" reports of Israeli air strikes on Syria and called on all concerned to prevent an escalation of tensions in the region. "At this time, the United Nations does not have details of the reported incident. Nor is the United Nations in a position to independently verify what has occurred," said a note issued by the UN chief office. "The Secretary-General calls on all concerned to prevent tensions or their escalation in the region, and to strictly abide by international law, in particular in respect of territorial integrity and sovereignty of all countries in the region," Ban's office said.