Iranian demonstrators crowded into the streets of Tehran and other cities on Thursday, with images circulating of government buildings on fire and the authorities blocking internet access but failing thus far to restore order.

Axar.az reports citing foreign media.

The intrigue: Early this week, U.S. intelligence assessed that the protests lacked sufficient energy to challenge the stability of the regime, U.S. officials told Axios. But that view is being reassessed in light of recent events.

"The protests are serious, and we will continue to monitor them," a senior U.S. official said.

Driving the news: The protests have grown and spread over the past 12 nights, with Thursday night's being the largest so far.

They are driven mainly by the country's economic turmoil, which has deepened amid President Trump's renewed push to tighten sanctions, and after the damage inflicted during the 12-day war in June.

Some of the crowds on Thursday were openly chanting for the downfall of the regime, according to various media reports.

What they're saying: Iranian President Masoud Pezeshkian, a reformer within the context of the theocratic regime, admitted in recent days that the Iranian government doesn't have solutions to the crisis.

He ordered the security forces on Thursday not to harm peaceful protesters, but to harm armed or violent rioters.

Iranian state media is downplaying the size of the protests. Meanwhile, the internet went down almost entirely nationwide on Thursday, according to NetBlocks.

Trump has warned multiple times that the U.S. could use military force if Iran kills protesters.

But he was relatively restrained when discussing the situation during an interview on Thursday on The Hugh Hewitt Show. Trump claimed some of the more than 30 protesters who have been killed so far died because of "problems of crowd control."

He also declined to endorse Reza Pahlavi, the son of the Shah who was deposed during the 1979 Islamic Revolution. Pahlavi has attempted the seized the political spotlight and called for more protests at 8 pm local time on Friday.

"I think that we should let everybody go out there, and we'll see who emerges," Trump said, adding that it wouldn't necessarily be "appropriate" for him to support Pahlavi.

What to watch: There were major protests in Iran in 2022, which weakened the regime but didn't bring it down.

Some hawkish figures in D.C. are expressing hope that, this time, the regime really does fall.

Senator Lindsey Graham (R-S.C.) called on Iranians to escalate the protest and stressed that Trump will back them. "Thugs, dictators, bullies, and killers who defy President Trump do not last long in this world. Make Iran Great Again," he wrote on X.