DUBAI, United Arab Emirates — Iran’s supreme leader on Wednesday rejected U.S. calls for surrender in the face of more Israeli strikes and warned that any military involvement by the Americans would cause “irreparable damage to them.” European diplomats prepared to hold talks with Iran on Friday.

The second public appearance by Ayatollah Ali Khamenei since the Israeli strikes began six days ago came as Israel lifted some restrictions on daily life, suggesting that the missile threat from Iran was easing.

Khamenei spoke a day after U.S. President Donald Trump demanded in a social media post that Iran surrender without conditions and warned Khamenei that the U.S. knows where he is but has no plans to kill him, “at least not for now.”

Trump initially distanced himself from Israel’s surprise attack aimed at Iran’s nuclear program, but in recent days he has hinted at greater American involvement, saying he wants something “much bigger” than a ceasefire. The U.S. has also sent more military aircraft and warships to the region.

Senior European diplomats were set to hold nuclear talks with Iran on Friday in Geneva, according to a European official familiar with the matter.

The official, who was not authorized to comment publicly and requested anonymity to discuss matters freely, said the meeting would include high-ranking diplomats from Germany, France and the United Kingdom, as well as the European Union’s top diplomat.

There are no plans for American involvement in the talks, although that could change, according to another U.S. official who spoke on condition of anonymity to discuss private diplomatic communications.

Separately, the U.N. Security Council scheduled a second emergency meeting on the Israel-Iran conflict for Friday at the request of Russia, China and Pakistan. Russian President Vladimir Putin offered to help mediate, suggesting Moscow could help negotiate a settlement allowing Tehran to pursue a peaceful atomic program while assuaging Israeli security concerns.

“In my view, a solution could be found,” Putin said Wednesday at a session with journalists.

In a video address to Israelis, Prime Minister Benjamin Netanyahu expressed appreciation for Trump’s support in the conflict, calling him “a great friend of Israel” and praising U.S. help defending Israel’s skies.

“We speak constantly, including last night,” he said Wednesday. “We had a very warm conversation.”

Khamenei dismissed the “threatening and absurd statements” by Trump.

“Wise individuals who know Iran, its people and its history never speak to this nation with the language of threats, because the Iranian nation is not one to surrender,” he said in a low-resolution video.

“Americans should know that any military involvement by the U.S. will undoubtedly result in irreparable damage to them.”

Iran released Khamenei’s statement before the video was aired, perhaps as a security measure. His location is not known, and it was impossible to discern from the tight shot, which showed only beige curtains, an Iranian flag and a portrait of Grand Ayatollah Ruhollah Khomeini, Khamenei’s immediate predecessor, who died in 1989.