President Trump on Saturday again expressed his support for Iran’s growing anti-government protests, saying oppressive regimes “cannot endure forever” and that “the world is watching.”

“Oppressive regimes cannot endure forever, and the day will come when the Iranian people will face a choice. The world is watching!” Trump said in two tweets. “The entire world understands that the good people of Iran want change, and, other than the vast military power of the United States, that Iran’s people are what their leaders fear the most....”

Against the backdrop of the Trump comments, reports emerged that the protests were escalating in their violence. Reuters said Saturday that videos posted on social media showed two young Iranian men lying motionless on the ground and covered with blood; a voiceover said they had been shot dead by police. It said security forces fired on protesters in the western town of Dorud and killed at least two. Other protesters in the same video were chanting, "I will kill whoever killed my brother!"

According to The Associated Press, the semiofficial news agency Fars said that in Tehran, up to 70 students gathered in front of its main university and hurled rocks at police. Social media footage showed riot police using clubs to disperse more protesters marching in nearby streets, and arresting some of them. The student news agency ISNA said police shut two metro stations to prevent more protesters arriving.

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And, AP reports said, in Tehran and Karaj west of the capital, protesters smashed windows on state buildings and set fires in the streets. Images carried by the semiofficial news agency Tasnim showed burning garbage bins and smashed-up bus shelters in the street lining the university after the protests subsided.

Trump’s increasingly forceful comments on the demonstrations mark the second time in two days that he has publicly backed the protests, amid growing support in Washington for the anti-government movement, largely sparked by Iranians’ frustration over rising food costs and continued high unemployment.

“The oppressive Iranian regime is of course trying to suppress the fact that protests against their tyrannical reign are popping up across Iran,” said Texas Rep. Will Hurd, a Republican member of the House Permanent Select Committee on Intelligence. “The Ayatollahs are out of touch with their citizens and are exporting terror abroad. We should support a free and peaceful Iran. We should support the people of Iran who have had enough.”

Earlier Saturday, Iran dismissed Trump’s public support Friday for the protests in the capital city of Tehran and elsewhere in the Arabian Gulf country.

“Iranian people give no credit to the deceitful and opportunist remarks of U.S. officials or Mr. Trump," said Iran Foreign Ministry spokesman Bahram Ghasemi, according to a state television report.

The protests began midweek in Mashhad, Iran’s second-largest city and a holy site for Shiite pilgrims. And they continued this weekend with hundreds of students and others protesting at Tehran University. Officials say roughly 50 protesters have so far been arrested.

"Many reports of peaceful protests by Iranian citizens fed up with regime's corruption & its squandering of the nation's wealth to fund terrorism abroad. Iranian govt should respect their people's rights, including right to express themselves. The world is watching! #IranProtests,” Trump tweeted late Friday.

Trump, since at least the start of his 2016 presidential campaign, has been critical of the Iranian leaders, arguing they have not fully complied with a 2015 international deal in which they agreed to curtail their pursuit of a nuclear weapon in exchange for the lifting of billions in crippling economic sanctions. The president, as a result, has refused to recertify the deal, brokered by the previous Obama administration.

The protests, sparked largely by social media, are also taking place amid previously planned pro-government rallies that have drawn a reported 4,000 people.

Ali Ahmadi, a 27-year-old pro-government demonstrator, blames the U.S. for all of Iran's economic problems.

“They always say that we are supporting Iranian people, but who should pay the costs?" he said.

Iran is run by Supreme Leader Ali Khamenei and elected President Hassan Rouhani.

Florida GOP Sen. Marco Rubio on Saturday also tweeted his support for the protests.

“All nations must hold the regime in Tehran fully accountable for any suppression of peaceful demonstrators in Iran,” he wrote. “The Iranian people have a right to peacefully protest the regime’s rampant corruption, and to call for a truly representative government that protects human rights, upholds the impartial rule of law, and seeks peace with all of its neighbors.”

The State Department late Friday also offered support to the protesters.

Social media videos show clashes between protesters and police. The semi-official Fars news agency said protests earlier this week also struck Qom, a city that is the world's foremost center for Shiite Islamic scholarship and home to a major Shiite shrine.

The demonstrations appear to be the largest to strike the Islamic Republic since the 2009 Green Movement, after Mahmoud Ahmadinejad was reelected president. However, information about the most recent protests remains scarce because neither state-run nor semi-official media in Iran have widely reported on them.

Iran's economy has improved since the nuclear deal. But that improvement has not reached the average Iranian. Official inflation has crept up to 10 percent again. And the price of eggs and poultry has recently increased by as much as 40 percent, though the government appears to blame to spike on fear of food contamination by avian flu.

While police have arrested some protesters, the country's powerful Revolutionary Guard and its affiliates have not intervened as they have in other unauthorized demonstrations since the 2009 election.

Secretary of State Rex Tillerson's comments in June to Congress saying American is working toward "support of those elements inside of Iran that would lead to a peaceful transition of that government" has been used by Iran's government of a sign of foreign interference in its internal politics.

The State Department issued a statement Friday supporting the protests, referencing Tillerson's earlier comments.

"Iran's leaders have turned a wealthy country with a rich history and culture into an economically depleted rogue state whose chief exports are violence, bloodshed and chaos," the statement said.

Iran's Foreign Ministry dismissed the comments.

"The noble Iranian nation never pays heed to the opportunist and hypocritical mottos chanted by the U.S. officials and their interfering allegations on domestic developments in the Islamic Republic of Iran," the state-run IRNA news agency quoted ministry spokesman Bahram Ghasemi as saying.

The Associated Press contributed to this report.