“I call for an immediate cessation of hostilities and de-escalation,” Guterres said in a statement, saying the attacks – including Iran’s retaliation – undermine international peace and security.

The secretary-general is to deliver further remarks at a Security Council meeting in New York at 4.00 pm (2100 GMT).

France, China, Russia, Bahrain and Colombia each led a push for the extraordinary Saturday meeting, according to a diplomatic source.

The Russian mission to the UN said it made the request over “the unprovoked act of armed aggression by the United States and Israel against the Islamic Republic of Iran”.

“During the Security Council meeting, we will demand that the US and Israel immediately cease their illegal and escalatory actions and embark on a path toward a political and diplomatic settlement,” it added in a statement.

In a letter to the UN, Iranian foreign minister Abbas Araghchi called on the Security Council to take “immediate” steps to halt what it said was an illegal aggression by the United States and Israel.

Araghchi said the council must “address the US and Israeli regimes’ acts of aggression” and “take the necessary and immediate measures to halt this unlawful use of force.”

“The US and the Israeli regime shall bear full and direct responsibility for all ensuing consequences, including any escalation arising from their unlawful actions,” he added in the letter.

The US and Israel on Saturday carried out a series of strikes citing “threats” from Iran, which responded with volleys of missiles aimed at Gulf states that host US bases and at Israel.