In a video provided by the Ukrainian Presidency, Ukrainian investigators collect parts of the Ukrainian airliner, Boeing 737 plane, Sunday, January 12.

READ MORE: The Ukraine International Airlines Boeing 737 was brought down by an Iranian missile shortly after taking off Wednesday from Tehran, killing all 176 passengers and crew on board.

Iran denied a "cover-up" Monday after taking days to reveal the airliner was accidentally shot down last week, a disaster that sparked demonstrations and calls for a fully transparent investigation.

The Kyiv-bound plane was knocked out of the sky hours after Tehran had launched a wave of missiles at two air bases in Iraq that house U.S. troops in retaliation for the killing of Iranian General Qassem Soleimani, head of the Iranian Quds Force.

Iran initially denied Western claims based on U.S. intelligence that the airliner had been struck by a missile before acknowledging it on Saturday.

Iran's handling of the matter saw country-wide demonstrations on Saturday before they was dispersed by police.

The videos showed protesters coughing and sputtering as they tried to escape the tear gas fumes (VOA could not independently verify the authenticity of the videos).

Tehran's police chief, Gen. Hossein Rahimi, insisted authorities treated protesters with "patience and tolerance."

In a speech before parliament, the head of the Revolutionary Guard apologized for the missile attack on the Ukraine International Airlines jet and insisted it was a tragic mistake, after three days of Iran denying any involvement in the plane crash.

Iranian Foreign Minister Javad Zarif, on Twitter, apologized for the shoot-down of the Ukraine International Airlines jet. But he contended that 'Human error at time of crisis caused by US adventurism led to disaster."

On Saturday in Tehran, protesters gathered near universities and called for the resignation of the country's supreme leader, Ayatollah Ali Khamenei, and chanted, "Down with liars!" and "Death to dictator!"

U.S. President Donald Trump warned Tehran against attacking the demonstrators.

"To the leaders of Iran - DO NOT KILL YOUR PROTESTERS," Trump said on Twitter. "Thousands have already been killed or imprisoned by you, and the World is watching. More importantly, the USA is watching. Turn your internet back on and let reporters roam free! Stop the killing of your great Iranian people!"



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