China's ambassador to the UN has condemned the US bombing of three nuclear facilities in Iran, and has called for an immediate ceasefire and an end to the hostilities.

"The actions of the United States seriously violate the purposes and principles of the UN Charter and international law, as well as Iran's sovereignty, security and territorial integrity," Ambassador Fu Cong said at an emergency meeting of the UN Security Council on Sunday.

"The international community must uphold justice and make concrete efforts to cool down the situation and restore peace and stability," Fu said.

The United States on Sunday send numerous B-2 bombers carrying "bunker buster" bombs into the airspace of Iran, where they severely damaged and possibly demolished Iranian nuclear facilities at Fordow, Natanz and Isfahan.

Final assessments of the damage are still pending.

With this action, the US joined Israel in its aim to destroy Iran's nuclear capabilities.

Iran reportedly responded to the US attack by firing 40 missiles targeting multiple sites in Israel, in the latest escalation of hostilities between the two Middle East nations. Since June 13, Israel has conducted large-scale strikes on Iranian military and nuclear facilities. However, Israel believed that destroying three of the facilities were beyond the capability of its own weaponry.

Iranian President Masoud Pezeshkian condemned the US attacks, saying, "This aggression shows that the United States is the primary instigator of ... hostile actions against the Islamic Republic of Iran."

Fu said: "Peace in the Middle East cannot be achieved by the use of force. Dialogue and negotiation are the fundamental way out. At present, diplomatic means to address the Iranian nuclear issue have not been exhausted, and there is still hope for a peaceful solution."

"Parties should stay firmly committed to the political settlement of the Iranian nuclear issue and work to bring it back onto the track of a political solution through dialogue and negotiation, with a view to reaching an agreement acceptable to all parties." Fu said.

At the emergency meeting, China, Russia and Pakistan proposed a draft resolution calling for an immediate ceasefire and an end to the hostilities, effective protection of civilians, a commitment to dialogue and negotiation, and swift action by the Security Council.

"The Security Council shoulders the primary responsibility for the maintenance of international peace and security. It cannot stand idly by in the face of a major crisis," Fu said.

"We hope that Council members can demonstrate their strong sense of responsibility by jointly supporting the draft resolution, to enable the Security Council to fulfill its responsibility for the maintenance of international peace and security," Fu said. "China stands ready to work with the international community to foster synergy, uphold justice and make unremitting efforts to restore peace and stability in the Middle East."

Antonio Guterres, secretary-general of the United Nations, said the bombing marked a perilous turn in the region. 

"We must act — immediately and decisively — to halt the fighting and return to serious, sustained negotiations on the Iran nuclear program," Guterres told the Security Council. "We need a credible, comprehensive and verifiable solution — one that restores trust — including with full access to inspectors of the IAEA, as the United Nations technical authority in this field."

"The people of the region cannot endure another cycle of destruction," he said. "And yet, we now risk descending into a rathole of retaliation after retaliation."

"To avoid it, diplomacy must prevail," Guterres said.