A group of Iranian protesters demanded Iran’s supreme leader Ali Khamenei step down on Saturday after Tehran said that its military had mistakenly shot down a Ukrainian plane, killing all 176 people on board. “Commander-in-chief (Khamenei) resign, resign,” videos posted on Twitter showed hundreds of people chanting, in front of Tehran’s Amir Kabir university. Reuters could not verify the authenticity of the video footage. Meanwhile, the semi-official Fars news agency, in a rare report on anti-government unrest, said other protesters in Tehran chanted slogans against the nation’s top authorities in wake of the downing of the jetliner. The report said the demonstrators on the street also ripped up pictures of Qassem Soleimani, the prominent commander of the Guard’s Quds Force who was killed in a US drone strike earlier this month. The agency, widely seen as close to the Guards, carried pictures of the gathering and a torn banner of Soleimani. It said the protesters numbered about 700 to 1,000 people. Earlier, Iran said its downing of the Ukraine jet was a "disastrous mistake", saying air defenses were fired in error while on alert after Iranian missile strikes on US targets in Iraq. Iran had denied for days after Wednesdays crash that it brought down the plane, although a top Revolutionary Guards commander said on Saturday that he had told authorities about the unintentional missile strike the day it happened. Foreign governments condemned Irans action, with Ukraine demanding compensation and a US official calling the downing reckless, although Britain said Tehrans admission was an important first step and urged a de-escalation in tensions. Khamenei, until now silent about the crash, said information about the incident should be made public, while top officials and the military issued apologies.