UNITED NATIONS -- The UN Security Council on Wednesday condemned "in the strongest terms" the deadly attacks on the US diplomatic mission and personnel in Benghazi, Libya, which killed the US ambassador and three other American diplomats.

The 15 council members "expressed their deep sympathy and sincere condolences to the victims of this heinous act and to their families," the council said in a press statement issued here.

"The members of the Security Council also condemned in the strongest terms the attack on the United States Embassy in Cairo, Egypt on 11 September," the statement said.

"The members of the Security Council underlined the need to bring perpetrators of these acts to justice," the statement said, "such acts are "unjustifiable regardless of their motivations, whenever and by whomsoever committed."

"The members of the Security Council recalled the fundamental principle of the inviolability of diplomatic and consular premises, and the obligations on host governments, including under the 1961 Vienna Convention on Diplomatic Relations and the 1963 Vienna Convention on Consular Relations, to take all appropriate steps to protect diplomatic and consular premises against any intrusion or damage, and to prevent any disturbance of the peace of these missions or impairment of their dignity, and to prevent any attack on diplomatic agents and consular officers," it said.

The Security Council also called on all authorities to protect diplomatic and consular property and personnel, and to respect their international obligations in this regard, it added.

"The members of the Security Council underscored the durable commitment of the international community to support Libya's successful transition to a peaceful and prosperous democracy," the statement added.

Hundreds of protesters, angered by an alleged US-made movie that insults the founder of Islam Prophet Mohammad, broke into the US consulate building in Benghazi on Tuesday night, and set ablaze the building.

Wanis Sharef, a Libyan deputy interior minister in charge of the country's security affairs in the east, confirmed to the press on Wednesday that the US ambassador to Libya, Christopher Stevens, 52, was killed along with three other US embassy staff when they went to the consulate to try to evacuate staff as the building came under attack by a mob armed with guns and rocket propelled grenades.