European foreign ministers were set to hold an emergency meeting on Sunday afternoon to discuss the conflict in Iran following the killing of the country's supreme leader Ayatollah Ali Khamenei.
Iranian state television and the state-run IRNA news agency announced the 86-year-old's death on Sunday morning.
United States president, Donald Trump, revealed on Saturday night that Khamenei's had died during a wave of Israeli and American bombings on Iran. Trump said the leader's death gave Iranians their greatest chance to take back their country.
On Sunday, Iran’s paramilitary Revolutionary Guard threatened to launch what it called its most intense offensive operation on Israel as well as American bases in the region.
"The Iranian regime's indiscriminate attacks against its neighbours carry the risk of dragging the region into a broader war and we condemn this," Kaja Kallas, the EU's foreign policy chief said on social media ahead of the video link meeting with the 27-nation bloc's foreign ministers.
"It is essential that the war does not spread any further. The Iranian regime has choices to make."
France's Macron insists on diplomacy to solve conflict in Iran and Middle East
Israeli military chiefs said on Sunday the bombardments, which also killed two top Iranian military commanders, would continue for a second day.
Trump added: "Heavy and pinpoint bombing will continue through the week or as long as necessary."
In France, President Emmanuel Macron emerged from an emergency meeting of top politicians and advisors on Saturday night to insist on a diplomatic solution to the unfolding conflict in Iran and the Middle East.
"Diplomatic efforts must resume their rightful place," said Macron after two hours of talks at the Elysée Palace in Paris with Foreign Minister Jean-Noël Barrot, Interior Minister Laurent Nunez, and Catherine Vautrin, Minister of Defence.
"I hope that we can take all necessary steps to ensure that diplomatic efforts resume."
The Elysée Palace said Macron would held a second meeting of the defence council on Sunday night.
EU urges diplomacy for Iran as Trump threatens strikes amid negotiations
Socialist party chief Olivier Faure, called for the involvement of the United Nations.
"It is urgent that the transition process be placed under the auspices of the UN in order to prevent chaos from following tyranny," he said on social media.
"The executioner Khamenei is dead. We will not mourn the man who, without hesitation, ordered the shooting of Iran's courageous youth in order to retain his power."
"My heart goes out to the Iranian people, who have been suffering under this bloodthirsty regime for 47 years," said Marine Tondelier, the leader of the Ecologists during an interview with French broadcaster France 3.
"I truly hope they will be able to free themselves from it. "But bombing has never democratised a country. And I would have preferred Ali Khamenei to be tried rather than killed."
National Rally chief Jordan Bardella said on social media: "The Iranian regime has been significantly weakened by the elimination of Ayatollah Khamenei, with its security structures severely affected.
"When the nation's higher interests are at stake, national unity is a duty. France must speak with a clear, strong and independent voice."
Khamenei's death came as Iranian and American diplomats were negotiating Iran's nuclear programme. Israel and the US attacked the country attacked Iran last June during similar talks aimed at limiting the Iran's ambitions for atomic power.
(With newswires)
