Around 150 people gathered for a pro-regime demonstration outside the main gate of Tehran University today, one day after social media videos appeared to show thousands of protesters chanting anti-regime slogans in the aftermath of Iran’s admission that it mistakenly shot down Ukraine International Airlines flight #PS752, an eyewitness told CNN.

The pro-government protesters also performed congregational prayers, the eyewitness said.

A second eyewitness said he heard the crowd chanting slogans in support of the Supreme Leader Ayatollah Ali Khamenei, a key target of protester anger during Saturday’s protests.

The same eyewitness said that regular police, riot police, Revolutionary Guard, and plain clothes officers were all seen stationed near Amirkabir University and are going in and out of nearby streets.

Night is falling in Tehran and it is unclear whether there will be a second night of anti-regime protestors.

Thousands of anti-government protesters gathered on Saturday outside the gates of Amir Kabir University, near the former US embassy in Tehran, to denounce the plane crash the government had blamed on human error and "US adventurism."

In a video posted on social media, protesters chanted for Supreme Leader Ayatollah Ali Khamenei to step down and for those responsible for downing the plane to be prosecuted. "Death to the dictator," some chanted. In one video, demonstrators chanted, "Khamenei have shame. Leave the country."

Security forces have been deployed in key areas of the capital, including Azadi Square near Sharif University, Engelab (Revolution) Square near Tehran University, and Ferdousi Square near some

Fully equipped riot police were on patrol, accompanied by water cannons and long black vehicles that are sometimes used as mobile detention centers.