BEIRUT — 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 from President Trump’s decision to kill a high-ranking Iranian general and Iran’s firing missiles at U.S. forces in Iraq in response.

After days of denials, Iran acknowledged Saturday that it had shot down the Ukraine International Airlines flight Wednesday, blaming the attack on human error. But the government’s obfuscation has angered many Iranians, already squeezed by poor economic conditions exacerbated by U.S. sanctions, and some took to the streets soon after.

Videos from inside Iran shared on social media 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.

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, head of Tehran’s police, said Monday, according to state-run news media.

Late Sunday, Trump warned Iran not to target the demonstrators. Framing himself as a supporter of the media, which in other circumstances he has frequently disparaged, Trump exhorted Iran’s leaders to allow unfettered reporting.

“Thousands have already been killed or imprisoned by you, and the World is watching,” he wrote on Twitter. “More importantly, the USA is watching. Turn your internet back on and let reporters roam free!”

The Ukrainian plane took off from Tehran on a flight to Kyiv, the Ukrainian capital, before dawn 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.

Tensions between the United States and Iran have soared since 2018, when Trump pulled the United States out of an international agreement limiting Iran’s nuclear program.

Ben Hubbard is a New York Times writer.