U.S. President Donald Trump said Iran wants to negotiate with Washington after his threat to strike the Islamic Republic over its crackdown on protesters in nationwide demonstrations that activists said Monday had left at least 599 people dead.

Iran had no direct reaction to Trump's comments, which came after the foreign minister of Oman — long an interlocutor between Washington and Tehran — traveled to Iran this weekend. It also remains unclear just what Iran could promise, particularly as Trump has set strict demands over its nuclear program and its ballistic missile arsenal, which Tehran insists is crucial for its national defense.

Iranian Foreign Minister Abbas Araghchi, speaking to foreign diplomats in Tehran, insisted “the situation has come under total control” in remarks that blamed Israel and the U.S. for the violence, without offering evidence.

“That’s why the demonstrations turned violent and bloody to give an excuse to the American president to intervene,” Araghchi said, in comments carried by Al Jazeera. The Qatar-funded network has been allowed to report live from inside Iran, despite the internet being shut off.

However, Araghchi said Iran was “open to diplomacy.” Iranian Foreign Ministry spokesman Esmail Baghaei said that a channel to the U.S. remained open, but talks needed to be “based on the acceptance of mutual interests and concerns, not a negotiation that is one-sided, unilateral and based on dictation.”

Meanwhile, pro-government demonstrators flooded the streets on Monday in support of the theocracy, a show of force after days of protests directly challenging the rule of 86-year-old Supreme Leader Ayatollah Ali Khamenei. Iranian state television aired chants from the crowd, which appeared to number in the tens of thousands, who shouted “Death to America!” and “Death to Israel!”

Others cried out: “Death to the enemies of God!” Iran’s attorney general has warned that anyone taking part in protests will be considered an “enemy of God,” a death-penalty charge.

Trump acknowledges proposal for talks

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

“The military is looking at it, and we’re looking at some very strong options,” Trump told reporters on Air Force One on Sunday night. Asked about Iran’s threats of retaliation, he said: “If they do that, we will hit them at levels that they’ve never been hit before.”

Trump said that his administration was in talks to set up a meeting with Tehran, but cautioned that he may have to act first as reports of the death toll in Iran mount and the government continues to arrest protesters.

“I think they’re tired of being beat up by the United States,” Trump said. “Iran wants to negotiate.”

Iran, through the country's parliamentary speaker, warned Sunday that the U.S. military and Israel would be “legitimate targets” if Washington uses force to protect demonstrators.

More than 10,600 people also 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 unrest in recent years and gave the death toll. It relies on supporters in Iran crosschecking information. It said 510 of the dead were protesters and 89 were security force members.

With the internet down in Iran and phone lines cut off, gauging the demonstrations from abroad has grown more difficult. The Associated Press has been unable to independently assess the toll. Iran’s government hasn't offered overall casualty figures.

Those abroad fear the information blackout is emboldening hard-liners within Iran’s security services to launch a violent crackdown. Protesters flooded Tehran's streets and its second-largest city on Saturday night into Sunday morning. Online videos purported to show more demonstrations Sunday night into Monday, with a Tehran official acknowledging them in state media.

At 2 p.m. Monday, Iranian state television showed images of demonstrators thronging Tehran toward Enghelab Square, or “Islamic Revolution” Square in the capital. It had been airing statements all morning from Iranian government, security and religious leaders to attend the demonstration.

It called the rally an “Iranian uprising against American-Zionist terrorism,” without addressing the underlying anger in the country over the nation’s ailing economy. State television aired images of such demonstrations around the country, trying to signal it had overcome the protests.

Fear pervades Iran's capital

In Tehran, a witness told the AP that the streets were empty at the sunset call to prayers each night. By the Isha, or nighttime prayer, the streets are deserted.

Part of that stems from the fear of getting caught in the crackdown. Police sent the public a text message that warned: “Given the presence of terrorist groups and armed individuals in some gatherings last night and their plans to cause death, and the firm decision to not tolerate any appeasement and to deal decisively with the rioters, families are strongly advised to take care of their youth and teenagers.”

Another text, which claimed to come from the intelligence arm of the paramilitary Revolutionary Guard, also directly warned people not to take part in demonstrations.

The witness spoke on condition of anonymity due to the ongoing crackdown.

The demonstrations began Dec. 28 over the collapse of the Iranian rial currency, which trades at more than 1.4 million to $1, as iran's economy is squeezed by international sanctions in part levied over its nuclear program. The protests intensified and grew into calls directly challenging Iran’s theocracy.

Video shows corpses outside capital

Meanwhile, video circulating online purports to show dozens of bodies in a morgue on the outskirts of Iran’s capital.

People with knowledge of the facility and the U.S.-based Human Rights Activists News Agency said Monday that the video shows the Kahrizak Forensic Medicine Center.

In the footage, people are seen walking by dozens of bodies in bags laid out in a large room, attempting to identify those there. In some cases, bodies can be seen lying outside on blue tarps. A large truck can be seen in part of the footage.