A crackdown on nationwide protests in Iran has killed at least 538 people and even more are feared dead, activists said Sunday, while Tehran warned that the U.S. military and Israel would be “legitimate targets” if America uses force to protect demonstrators.

More than 10,600 people have been detained over the two weeks of protests, said the U.S.-based Human Rights Activists News Agency, which has been accurate in previous rounds of unrest in Iran in recent years. It relies on activists in Iran crosschecking information.

The Iranian government has not offered overall casualty figures for the demonstrations. The Associated Press has been unable to independently assess the toll, given that internet and international phone calls are now blocked in Iran.

Those abroad fear the information blackout will embolden hardliners within Iran’s security services to launch a bloody crackdown, despite warnings from U.S. President Donald Trump he’s willing to strike Iran to protect peaceful demonstrators.

Trump offered support for the protesters, saying on social media that “Iran is looking at FREEDOM, perhaps like never before. The USA stands ready to help!!!”

Trump and his national security team have been weighing a broad range of potential responses against Iran including cyberattacks and direct strikes by either U.S. or Israel, according to two people familiar with internal White House discussions who were not authorized to comment publicly and spoke on condition of anonymity.

The White House, which did not immediately respond to a request for comment, has not indicated it has made any decisions. The massive ongoing U.S. military deployment to the Caribbean has created another factor that the Pentagon and Trump’s national security planners must consider.

WATCH | Protest images have emerged despite an internet blackout:

Fiery Iran protest images emerge as Trump threatens regime

Fiery images of anti-regime protests are emerging from Iran despite the government cutting phone and internet services. U.S. President Donald Trump has threatened action against the regime if it starts killing people, while human rights groups say dozens have already died.Parliament rallies

The threat to strike the U.S. military and Israel came during a parliamentary speech Sunday from Mohammad Baagher Qalibaf, the hardliner speaker who has run for the presidency in the past.

He directly threatened Israel, “the occupied territory” as he referred to it, and the U.S. military, possibly with a pre-emptive strike.

“In the event of an attack on Iran, both the occupied territory and all American military centres, bases and ships in the region will be our legitimate targets,” Qalibaf said. “We do not consider ourselves limited to reacting after the action and will act based on any objective signs of a threat.”

Lawmakers rushed the dais in the Iranian parliament, shouting: “Death to America!”

It remains unclear just how serious Iran is about launching a strike, particularly after its air defenses were destroyed during the 12-day war in June with Israel. Any decision to go to war would rest with Iran’s Supreme Leader Ayatollah Ali Khamenei.

The U.S. military has said in the Middle East it is “postured with forces that span the full range of combat capability to defend our forces, our partners and allies and U.S. interests.” Iran targeted U.S. forces at Al Udeid Air Base in Qatar back in June, while the U.S. Navy’s Mideast-based 5th Fleet is stationed in the island kingdom of Bahrain.

Israel, meanwhile, is “watching closely” the situation between the U.S. and Iran, said an Israeli official, who spoke on condition of anonymity due to not being authorized to speak to journalists. Israeli Prime Minister Benjamin Netanyahu spoke with U.S. Secretary of State Marco Rubio overnight on topics including Iran, the official added.

At the Vatican, Pope Leo XIV mentioned Iran as a place “where ongoing tensions continue to claim many lives.”

“I hope and pray that dialogue and peace may be patiently nurtured in pursuit of the common good of the whole of society,” he said.

Protests in Tehran and Mashhad

Online videos sent out of Iran, likely using Starlink satellite transmitters, purportedly showed demonstrators gathering in northern Tehran’s Punak neighborhood. There, it appeared authorities shut off streets, with protesters waving their lit mobile phones. Others banged metal while fireworks went off.

“The pattern of protests in the capital has largely taken the form of scattered, short-lived, and fluid gatherings, an approach shaped in response to the heavy presence of security forces and increased field pressure,” the Human Rights Activists News Agency said.

“Reports were received of surveillance drones flying overhead and movements by security forces around protest locations, indicating ongoing monitoring and security control.”

In Mashhad, Iran’s second-largest city some 725 kilometres northeast of Tehran, footage purported to show protesters confronting security forces. Flaming debris and dumpsters could be seen in the street, blocking the road. Mashhad is home to the Imam Reza shrine, the holiest in Shiite Islam.

Ali Larijani, a top security official, went on state TV to accuse some demonstrators of “killing people or burning some people, which is very similar to what ISIS does,” referring to the Islamic State group by an acronym. State TV aired funerals of slain security force members while reporting another six had been killed in Kermanshah. It also showed a pickup truck full of bodies in body bags and later a morgue.

WATCH | Expert discusses whether the latest protests will be any different:

Protests spread in Iran again — is this time different? | Hanomansing Tonight

Iran has faced rounds of demonstrations in recent years, from the Green Movement to the Mahsa Amini protests — but none have toppled Ayatollah Ali Khamenei’s government. Kamran Bokhari from the New Lines Institute discusses whether the latest protests will be any different.

Even Iran’s reformist President Masoud Pezeshkian, who had been trying to ease anger before the demonstrations exploded in recent days, offered a hardening tone in an interview aired Sunday.

“People have concerns, we should sit with them and if it is our duty, we should resolve their concerns,” Pezeshkian said. “But the higher duty is not to allow a group of rioters to come and destroy the entire society.”

Iran’s exiled Crown Prince Reza Pahlavi asked in his latest message for demonstrators to take to the streets Sunday.

Pahlavi’s support of and from Israel has drawn criticism in the past, particularly after the 12-day war. Demonstrators have shouted in support of the shah in some protests, but it isn’t clear whether that’s support for Pahlavi himself or a desire to return to a time before the 1979 Islamic Revolution.