Mahdi Karoubi, one of the leaders of the opposition green movement in Iran, called on the Iranian guide, Ayatollah Ali Khamenei, to step down due to the downing of the Ukrainian plane, amid university students' protests against the regime.
In a statement on the website of Saham News, Karoubi asked about the date of Khamenei's knowledge of the shooting down of the plane after it took off from Tehran on Wednesday, and the reason for the delay in informing the public of the actual causes of the crash.
On Saturday, Iranian police dispersed students who were chanting slogans during their gathering in Tehran for what he described as "a tribute" to the victims of the Ukrainian plane that was accidentally hit by an Iranian missile, according to Fars News Agency.
According to Agence France-Presse, hundreds of students gathered at Amir Kabir University in central Tehran condemning the regime, and the "gathering" later turned into a furious demonstration.
The students chanted slogans condemning the "liars", calling for the resignation of those responsible for the downing of the plane, coverage of the accident and their trial.
Iran admitted Saturday that it had downed a "mistake" a Ukrainian civilian plane and offered its apology, pointing to the responsibility of the "American adventure trend" in this tragedy that killed 176 people.
Twitter footage showed protesters calling for Khamenei's resignation. Hundreds of people chanted in front of Amir Kabir University in Tehran, "The sweetest solution, Supreme Leader (Khamenei)."
The Fars news agency said the students chanted "subversive" and "extremist" slogans, adding that some students tore down pictures of the late Iranian general, Qasim Soleimani, who was killed on January 3 by an American strike in Baghdad.
Faris also published pictures of demonstrators gathered around a ring of candles during the protest, in addition to a torn picture of Soleimani.
She said the police "dispersed them" after they left the campus and closed the streets, causing traffic jams.
Iranian state television referred to the demonstration, stressing that the students were chanting "against the regime."
The commander of the Air Force-Space of the Revolutionary Guards, Brigadier Amir Ali Haji Zada, has declared that he bears "full responsibility" for the Ukrainian plane tragedy.
The brigadier general said that the soldier who fired the missile believed the plane was a "cruise missile." He added that he tried to communicate with higher-ranking leaders to "verify the target" but was unable to do so because he "apparently had trouble" in the communications system.
US President Donald Trump endorsed the protesters and said in a tweet on Twitter, "We follow your protests closely and your courage is an inspiration." He said he was not seeking "regime change" in Iran.
"The Iranian government must allow human rights groups to monitor and announce facts on the ground about the ongoing protests of the Iranian people. There cannot be another massacre of peaceful protesters, nor can the Internet be shut down. The world is watching," he added.
The British Foreign Office confirmed late Saturday evening that the Iranian authorities had detained the British ambassador to Tehran, Rob Macer, for a short period, and condemned the move as "a flagrant violation of international law."
Earlier, Tasnim News Agency reported that Machir was arrested for several hours in front of Amir Kabir University for inciting anti-government protesters.