Ukrainian President Volodymr Zelensky landed in London on Monday and will meet with British Prime Minister Keir Starmer and other officials, a senior Ukrainian source told AFP.

"There will be plenty of meetings, with the prime minister and parliament," the source said.

The U.N. nuclear watchdog head demanded Monday the return of agency inspectors to Iran's nuclear sites in a bid to "account for" its highly enriched uranium stockpiles following attacks by Israel and the United States on its atomic program.

To be able to "return to the negotiating table", "allow IAEA inspectors, the guardians on our on behalf of the NPT to go back to Iran's nuclear sites and account for the stockpiles of uranium" including the "400 kilograms enriched to 60 percent", Rafael Grossi, director of the International Atomic Energy Agency (IAEA), told an emergency meeting of the organization's headquarters in Vienna.

The EU's top diplomat warned Monday it would be "extremely dangerous" should Iran shut down the crucial Strait of Hormuz trading route over U.S. strikes on its nuclear sites.

"Any Iranian closure of the Strait of Hormuz would be extremely dangerous," Kaja Kallas wrote on X, as EU foreign ministers met in Brussels for talks with the Iran-Israel conflict high on the agenda.

Shortly after U.S. B-2 bombers began their return to the U.S. after they struck Iran’s key nuclear facilities, U.S. President Donald Trump called Israeli Prime Minister Benjamin Netanyahu to brief him on the strike, U.S. and Israeli officials told U.S. news portal Axios.

Russia fired 352 drones and 16 missiles at Ukraine overnight, killing at least seven people in the capital Kyiv and its suburbs, Ukrainian President Volodymyr Zelensky said on Monday.

"In total, 352 drones were launched, including 159 (Iranian-designed) Shaheds just overnight, along with 16 missiles. Preliminary reports indicate that ballistic weapons from North Korea were also used," Zelensky said on social media.

Iran said Monday the attacks launched on the Islamic republic during talks about its nuclear program were a "betrayal of diplomacy".

"We and future generations will not forget that the Iranians were in the middle of a diplomatic process with a country that is now at war with us," said foreign ministry spokesman Esmaeil Baqaei.

Iran's Foreign Minister Abbas Araghchi on Sunday condemned US attacks on key nuclear sites as "outrageous" and said his country has a right to defend its sovereignty.

"The events this morning are outrageous and will have everlasting consequences," he posted on X, adding that the attacks were "lawless and criminal" behaviour.

The U.N.'s International Atomic Energy Agency (IAEA) on Sunday said that it had not detected any increase in radiation levels at key nuclear sites in Iran following U.S. air strikes.

U.S. President Donald Trump said U.S. air strikes on Sunday "totally obliterated" Iran's main nuclear sites, as Washington joined Israel's war with Tehran in a flashpoint moment for the Middle East.

In a televised address to the nation from the White House, Trump warned that the United States would go after more targets if Iran did not make peace quickly.

U.S. President Donald Trump said overnight that Iran had a "maximum" of two weeks to avoid possible U.S. air strikes, indicating he could take a decision before the fortnight deadline he set a day earlier.