A senior UN official on Tuesday urged the Security Council to work to avert further escalation in the Middle East following the deadly airstrike on the Iranian consulate in Syria’s capital, Damascus, according to the UN News Center.

Briefing ambassadors a day after the attack, Assistant-Secretary-General Khaled Khiari reportedly stressed the need for restraint. 

“We appeal to the Council today, as we do every month, to continue to actively engage all concerned parties to prevent further escalation and the worsening of tensions that undermine regional peace and security,” he said.

UN Secretary-General António Guterres has condemned the attack, his spokesperson said on Tuesday, reaffirming that the principle of the inviolability of diplomatic and consular premises and personnel must be respected in all cases.

The UN chief reminded all parties to respect all their obligations under international law, and urged all concerned to avoid attacks that could harm civilians and damage civilian infrastructure.

Mr. Khiari said Iran sent identical letters to the Secretary-General and the Security Council on Monday stating that Israel had attacked its diplomatic premises in Damascus, killing at least five personnel, including senior military advisors, and injuring others.

Subsequent media reports indicate that the death toll has risen to 13 - seven Iranian personnel and six Syrian citizens, he added, before reiterating the Secretary-General’s condemnation.

“The sovereignty and territorial integrity of Member States must be respected in accordance with international law,” said Mr. Khiari, whose portfolio straddles political and peacebuilding affairs as well as peace operations.

“The rules-based international order is essential for international peace and security, which this Council is mandated to maintain.”

He recalled that the UN Special Envoy for Syria, Geir Pedersen, has kept the Council apprised of the unrelenting violence in the country, which recently marked 13 years of war.

Six foreign armies are operating on Syrian territory impacting the lives of civilians and putting a peaceful resolution of the conflict farther out of reach.