Iran denies a "cover-up" after it took days for the armed forces to admit a Ukrainian airliner was shot down by mistake last week

Iran's Supreme Leader Ayatollah Khameini 

Iran's government on Monday denied a "cover-up" after its armed forces took three days to admit that a passenger plane was downed by mistake last week.

"In these sorrowful days, many criticisms were directed at relevant officials and authorities... some officials were even accused of lying and a cover-up but, in all honesty, that was not the case," spokesman Ali Rabiei said in remarks aired on state television.

Police denied shooting protesters

Meanwhile, Tehran's police chief has denied that Iranian police officers shot at demonstrators protesting the downing of the Ukrainian International Airlines jet, that left all 176 passengers dead. Hassan Roheimi said that officers had been ordered to "show restraint," in a statement carried by Iran's state broadcaster.

The denial was in response to footage on social media which purported to show Iranian police and security forces firing both live ammunition and tear gas at demonstrators in Tehran.

The videos, which were posted by the New York-based Center for Human Rights in Iran on Sunday, could not be immediately verified. The images also showed blood on the ground and security personnel carrying rifles in the area. Meanwhile, other social media posts supposedly showed images of police in riot gear hitting demonstrators with batons.

Angry protests erupt in Iran over response to plane crash

Another video shows a woman being carried away from the protests, while people around her call out that she has been shot in the leg by live ammunition. The events allegedly took place at Azadi (Freedom) square in Tehran. Police also patrolled at Vali-e Asr Square, at Tehran University, and other landmarks around the city.

Iran recognizes culpability in fatal Ukrainian jet crash

Demonstrators' demands

Demonstrators were gathering to demand the resignation of all officials who played a role in the Ukrainian International Airlines traged, and to denounce the immediate concealment of the facts.

Protesters were also filmed on Sunday chanting "Death to the dictator," referring to Khameini. Other chants included "They are lying that our enemy is America, our enemy is right here."

Iran dismisses Trump's tweeted support for Iranians 

US President Donald Trump also voiced his support for demonstrators in Iran on Sunday and Monday, writing, "To the leaders of Iran - do not kill your protesters... The world is watching."

Iran's government spokesman dismissed tweets by US President Donald Trump voicing support for Iranians, saying the Iranian people would remember he killed general Soleimani and was the reason many were facing economic challenges, state media said.

Trump, who told Iran's authorities in tweets published in both Farsi and English not to kill protesters and praised the "great Iranian people", was shedding "crocodile tears" when voicing concern for Iranians, Ali Rabiei said.

The downing of the Ukrainian International Airlines jet has sparked new demonstrations and calls for Iran's Supreme Leader Ayatollah Khameini to resign. The downing occurred hours after Iran had fired at US bases to retaliate for the killing of Iran's most powerful military leader, Qassem Soleimani.

After blaming the event on a technical failure for three days, Iranian authorities took responsibility for the downing of the plane, calling it an "unforgivable mistake."