Israel appeared to be expanding its air campaign on Tehran five days after its surprise attack on Iran's military and nuclear program, as U.S. President Donald Trump posted an ominous message warning residents of the city to evacuate.

“IRAN CAN NOT HAVE A NUCLEAR WEAPON,” Trump wrote Monday night before returning to Washington early from a Group of Seven summit in Canada. “Everyone should immediately evacuate Tehran!” he added.

China on Tuesday accused President Donald Trump of "pouring oil" on the mounting conflict between Iran and Israel, after the U.S. leader warned Tehran residents to "immediately evacuate".

"Fanning the flames, pouring oil, making threats and mounting pressure will not help to promote the de-escalation of the situation, but will only intensify and widen the conflict," foreign ministry spokesman Guo Jiakun said when asked about Trump's remarks at a regular news conference.

Volodymyr Zelensky on Monday said that he will discuss buying U.S. weapons with Donald Trump at the G7 summit, but added that U.S. military aid was not on the agenda.

"We are not talking to America today about new assistance. Indeed, one of the issues I will discuss with President Trump at the meeting is the defense package that Ukraine is ready to buy," Zelensky said during a visit to Vienna, from where he is set to travel to Canada for this week's G7 summit.

Russia said Monday that the United States had cancelled a fresh round of talks on normalizing the operations of their embassies.

"The next meeting... has been cancelled at the initiative of the American negotiators. We hope that the pause they have taken will not be too long," Russian foreign ministry spokeswoman Maria Zakharova said.

Ukrainian President Volodymyr Zelensky is visiting Austria on Monday in his first trip to the European Union member country since Russia's full-scale invasion of Ukraine in 2022.

Austria is famously neutral — a stance it declared in 1955 after World War II — and Vienna has come under heavy criticism since the start of the Russia-Ukraine war for maintaining ties with Moscow.

Former Syrian official and adviser to ousted President Bashar al-Assad has been interviewed in Beirut by the FBI and the CIA in April, in the presence of Lebanese officials, The Washington Post and the British Broadcasting Corporation (BBC) said Sunday.

According to the reports, Bassam al-Hassan told the FBI that American journalist Austin Tice was killed in 2013 on the orders of al-Assad, after Tice briefly escaped from his prison cell.

The head of the International Atomic Energy Agency said Monday that there is a possibility of both radiological and chemical contamination within Iran's main nuclear enrichment facility in Natanz following Israeli strikes, although radiation levels outside the complex are presently normal.

IAEA director general Rafael Mariano Grossi said that the radiation poses a significant danger if uranium is inhaled or ingested. He added that the risk can be effectively managed with appropriate protective measures, such as using respiratory protection devices while inside the facilities.

Russian President Vladimir Putin and Turkish counterpart Recep Tayyip Erdogan called Monday for an "immediate" end to fighting between Israel and Iran in a phone conversation, the Kremlin said.

"The leaders called for an immediate end to hostilities and the settlement of contentious issues, including those related to Iran's nuclear program, exclusively through political and diplomatic means," the Kremlin said in its readout of the call.

Iran on Monday accused Israel of targeting a hospital in the country's west, condemning it as a "war crime".

"Farabi Hospital in the city of Kermanshah in western Iran was targeted by the Israeli regime's aggressive attacks," said foreign ministry spokesman Esmaeil Baqaei, adding that "attacking hospitals alongside attacks on residential areas is a gross violation of international law and a war crime".

France on Monday blocked access to the stands of five Israeli arms manufacturers at the Paris Air show for displaying "offensive weapons", according to a French government source.

A black wall blocked off stands run by Israel Aerospace Industries (IAI), Rafael, Uvision, Elbit and Aeronautics for showing "offensive weapons", including those used in Gaza, which allegedly violated terms made with Israel, said the source.