Iran launched explosive drones and fired missiles at Israel late on Saturday in its first direct attack on Israeli territory, a retaliatory strike that raised the threat of a wider regional conflict, as the U.S pledged "ironclad" backing for Israel.

Sirens wailed and Reuters journalists in Israel heard distant heavy thuds and bangs from what local media called aerial interceptions of explosive drones. Authorities said a 7-year-old girl was critically injured.

U.S. President Joe Biden, who spoke by phone with Israeli Prime Minister Benjamin Netanyahu, said he would convene a meeting of leaders of the Group of Seven major economies on Sunday to coordinate a diplomatic response to what he called Iran's brazen attack.

Six months into an Israeli-Hamas war in Gaza and amid growing risks of a greater regional war, Axios quoted a senior White House official as saying Biden also told Netanyahu the U.S. would oppose any Israeli counterattack against Iran.

The U.N. Security Council was set to meet at 4 p.m. ET (2000 GMT) on Sunday after Israel requested it condemn Iran's attack and designate the Iranian Revolutionary Guard Corps a terrorist organization, according to a schedule released late on Saturday.

Israel's military spokesperson, Rear Admiral Daniel Hagari, said Iran launched dozens of ground-to-ground missiles at Israel, most of them intercepted outside Israeli borders. They included more than 10 cruise missiles, he said.

The Iranian salvo of more than 200 drones and missiles caused light damage to one Israeli military facility, Hagari said.

The Israeli military later said it was not advising any residents to prepare to take shelter. This revision of an earlier alert appeared to signal the end of the threat

Israel's Channel 12 TV cited an unnamed Israeli official as saying there would be a "significant response" to the attack.

Iran had vowed retaliation for what it called an Israeli strike on its Damascus consulate on April 1 that killed seven officers of the Islamic Revolutionary Guard Corps, including two senior commanders. Tehran said its strike was punishment for "Israeli crimes". Israel has neither confirmed nor denied responsibility for the consulate attack.

"Should the Israeli regime make another mistake, Iran's response will be considerably more severe," the Iranian mission to the United Nations said, warning the U.S. to "stay away". However, it also said Iran now "deemed the matter concluded".

U.S. Defense Secretary Lloyd Austin said America did not seek conflict with Iran but would not hesitate to act to protect U.S. forces and support defence of Israel.

United Nations Secretary-General Antonio Guterres condemned Iran's attack, saying he was "deeply alarmed about the very real danger of a devastating region-wide escalation."

Russian Deputy U.N. Ambassador Dmitry Polyanskiy said on the Telegram social media app that in addition to a letter from Israel, the Security Council had received one from Iran asserting its attack was within the U.N. Charter framework governing the right to self-defence.

"The latter warns that if Israel responds, Iran will respond in a more powerful and decisive manner," Polyanskiy said.

Biden, who on Friday had warned Iran against an attack, cut short a weekend visit to his home state of Delaware and returned to Washington to meet with his national security advisers, including his secretaries of defence and state, in the White House Situation Room. He pledged to stand with Israel.