BEIRUT, Lebanon — Protesters and riot police faced off in at least two cities in Iran on Monday, a third day of angry demonstrations at the country’s leaders after the government acknowledged having shot down a Ukrainian passenger plane, killing 176 people.
The protests are the most recent spillover from escalating regional tensions between the United States and Iran that built up to President Trump’s decision to kill a high-ranking Iranian general, and Iran’s firing missiles at United States forces in Iraq in response.
After days of denials, Iran acknowledged early on Saturday that it had shot down the Ukraine International Airlines flight on Wednesday, blaming the attack on human error. But the government’s obfuscation has angered many Iranians, already squeezed by poor economic conditions exacerbated by United States sanctions, and some took to the streets soon after.
Videos from inside Iran shared on social media on Monday showed university students in Isfahan and the capital, Tehran, chanting against the country’s clerical rulers while riot police deployed nearby.
The extent of the protests and the amount of violence used to try to stop them were hard to assess because of tight restrictions on social media and the news media inside the country. Videos from previous days have shown protesters carrying off bleeding comrades while gunshots echoed in the background.
The authorities in Iran denied that security forces had opened fire.
“At protests, police absolutely did not shoot because the capital’s police officers have been given orders to show restraint,” Hossein Rahimi, the head of Tehran’s police, said on Monday, according to state-run news media.
Late Sunday, Mr. Trump warned Iran not to target the demonstrators. Framing himself as a supporter of the media, which in other circumstances he has frequently disparaged, Mr. Trump exhorted Iran’s leaders to allow unfettered reporting.
“To the leaders of Iran — DO NOT KILL YOUR PROTESTERS,” he wrote on Twitter. “Thousands have already been killed or imprisoned by you, and the World is watching. More importantly, the USA is watching. Turn your internet back on and let reporters roam free! Stop the killing of your great Iranian people!”
The Ukrainian plane took off from Tehran on a flight to Kyiv, the Ukrainian capital, before dawn on Wednesday, and barely two minutes later it was struck by an anti-aircraft missile fired by an Iranian crew. Iranian forces had fired missiles at American forces in Iraq hours earlier, and were on the alert for retaliation by the United States.
In addition to the domestic outrage, Iran may also face demands for compensation from nations whose citizens were killed on the plane, Foreign Minister Vadym Prystaiko of Ukraine told Reuters on Monday in an interview in Singapore.
“We have created this group of foreign ministers from the grieving nations. On Jan. 16, we will meet in person in London to discuss the ways, including legal, how we are following this up, how we are prosecuting them,” Mr. Prystaiko said, referring to the Iranians.
The talks would include five nations, he said: Canada, which lost 57 citizens, Ukraine, Afghanistan, Sweden and another country he did not identify.
They and other nations have pushed for greater international involvement in the investigation of how the crash happened, and Mr. Prystaiko said Tehran had agreed to hand over the jet’s black boxes for analysis, but had yet to set a date to do so.
Mr. Prystaiko separately told the BBC in an interview broadcast Monday that President Hassan Rouhani of Iran had accepted full responsibility for the crash, without trying to shift the blame onto the United States for escalating overall tensions in the region.
“At least at the presidential level, nothing of this nonsense was mentioned,” Mr. Prystaiko said, describing Mr. Rouhani’s phone call with President Volodymyr Zelensky of Ukraine on Saturday. “He tried to do his best to explain that it was human error, that no one who is to be punished will escape the punishment.”
Tensions between the United States and Iran have soared since 2018, when Mr. Trump pulled the United States out of an international agreement limiting Iran’s nuclear program and imposed the first in a series of sanctions on Iran to punish it for what his administration sees as its destabilizing activities across the Middle East.
After a number of attacks on United States assets and allies in the Middle East in recent months, Mr. Trump ordered the killing on Jan. 3 of Maj. Gen. Qassim Suleimani, the commander of Iran’s Quds force. He headed Iran’s efforts to support and direct allied militias in the region.
Those militias include an Iraqi group that fired rockets at a military base in Iraq late last month, killing one American contractor. United States forces retaliated against militia bases, killing more than two dozen fighters, and militias responded by surrounding the American Embassy compound in Baghdad, breaching its perimeter wall, setting fires and throwing rocks.
The killing of General Suleimani in a drone strike at the Baghdad airport raised fears that Iran or its network of allies across the Middle East would respond against the United States and its allies, possibly igniting a regional war.