President Donald Trump said the U.S. may meet Iranian officials and was in contact with the opposition, as he weighed a range of strong responses including military options to escalating unrest posing one of the biggest challenges to clerical rule since the 1979 Islamic Revolution
Trump said Iran called to negotiate its nuclear program, which Israel and the U.S. bombed in a 12-day war in June. Trump has warned Iran's leaders that the United States would attack if security forces open fire on protesters.
U.S.-based rights group HRANA said it had verified 538 deaths, including 490 protesters and 48 security personnel, with more than 10,600 people arrested.
Iran has not given an official toll and Reuters was unable to verify the tallies independently.
Trump was to meet with senior advisers Tuesday to discuss options for Iran, a U.S. official told Reuters on Sunday. The Wall Street Journal had reported that options included military strikes, using secret cyber weapons, widening sanctions and providing online help to anti-government sources.
"The military is looking at it, and we're looking at some very strong options," Trump told reporters traveling on Air Force One on Sunday night.
Iranian Parliament Speaker Mohammad Bagher Qalibaf warned Washington against "a miscalculation."
"Let us be clear: in the case of an attack on Iran, the occupied territories (Israel) as well as all U.S. bases and ships will be our legitimate target," said Qalibaf, a former commander in Iran's elite Revolutionary Guards.
Dozens of body bags
The protests began on Dec. 28 in response to soaring prices, before turning against the clerical rulers who have governed since the 1979 Islamic Revolution.
Iranian authorities accused the U.S. and Israel of fomenting trouble and called for a nationwide rally Monday to condemn "terrorist actions led by the United States and Israel," state media reported.
The flow of information from Iran has been hampered by an internet blackout since Thursday. Trump said Sunday he would talk to Elon Musk about restoring internet access in Iran through his Starlink satellite service.
Footage posted on social media Saturday from Tehran showed large crowds marching at night, clapping and chanting. The crowd "has no end nor beginning," a man is heard saying.
State TV showed dozens of body bags on the ground at the Tehran coroner's office, saying the dead were victims of events caused by "armed terrorists," as well as footage of loved ones gathered outside the Kahrizak Forensic Medical Centre in Tehran waiting to identify bodies.
Reuters verified the locations.
Authorities declared Sunday three days of national mourning "in honor of martyrs killed in resistance against the United States and the Zionist regime," according to state media.
Three Israeli sources, who were present for Israeli security consultations over the weekend, said Israel was on a high alert footing for the possibility of any U.S. intervention.
Israel and Iran fought a 12-day war in June 2025, which the United States briefly joined by attacking nuclear installations. Iran retaliated by firing missiles at Israel and an American air base in Qatar.
'Rioters and terrorists'
While Iranian authorities have weathered previous protests, the latest have unfolded with Tehran still recovering from last year's war and with its regional position weakened by blows to allies such as Lebanon's Hezbollah since the Oct. 7, 2023, Hamas incursion.
Iran's unrest comes as Trump flexes U.S. muscles internationally, having ousted Venezuelan President Nicolas Maduro and discussing acquiring Greenland by purchase or force.
Alan Eyre, a former U.S. diplomat and Iran expert, thought it unlikely the protests would topple the establishment.
"I think it's more likely that it puts these protests down eventually, but emerges from the process far weaker," he told Reuters, noting that Iran's elite still appeared cohesive and there was no organized opposition.
Trump, posting on social media on Saturday, said: "Iran is looking at FREEDOM, perhaps like never before. The USA stands ready to help!!!"