China has strongly condemned the United States' attacks on Iran and the bombing of nuclear facilities under the safeguards of the International Atomic Energy Agency, according to a statement released on Sunday by the Chinese Foreign Ministry.

The US attacked three sites in Iran early on Sunday, inserting itself into Israel's conflict with Iran aimed at destroying the latter's nuclear program.

The Atomic Energy Organization of Iran confirmed that the attacks took place at its Fordow, Natanz and Isfahan sites. Iran and the IAEA, the United Nations nuclear watchdog, said there were no immediate signs of radioactive contamination at the three locations.

The actions of the US seriously violated the purposes and principles of the UN Charter and international law, and have exacerbated tensions in the Middle East, the Foreign Ministry said.

China calls on the parties to the conflict, and Israel in particular, to reach a ceasefire as soon as possible, ensure the safety of civilians and start dialogue and negotiation, the statement said, adding that China stands ready to work with the international community to pool efforts and uphold justice, and work for restoring peace and stability in the Middle East.

In a national address at the White House after the attacks, US President Donald Trump said: "Our objective was the destruction of Iran's nuclear enrichment capacity and a stop to the nuclear threat. ... There's no military in the world that could have done what we did tonight."

He said that Iran's key nuclear sites have been "completely and fully obliterated".

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. In retaliation, Iran launched multiple missile and drone attacks on targets in Israel.

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."

UN Secretary-General Antonio Guterres said he was "gravely alarmed" by the US' use of force. "There is a growing risk that this conflict could rapidly get out of control — with catastrophic consequences for civilians, the region and the world," he said in a statement.