Protests in Iran continue to escalate as the country struggles to control public anger over the Iranian military's shooting down of a Ukrainian passenger plane, carrying 176 people.
Police used tear gas to disperse hundreds of demonstrators chanting against the country's leaders - including Supreme Leader Ayatollah Ali Khamenei - on the second day of protests in Tehran, with rallies spreading to other Iranian cities.
Videos posted online appear to show blood-soaked pavements and protesters shouting anti-government slogans as chaos ensued on the streets of the capital.
Another clip circulating on social media purports to show a woman in pain after being shot in the leg.
Riot police in black uniforms and helmets earlier massed in Vali e Asr Square, at Tehran University and other landmarks.
That prompted US President Donald Trump, who has previously supported anti-government demonstrations in Iran, to tweet: "To the leaders of Iran - DO NOT KILL YOUR PROTESTERS."
He later tweeted: "National Security Adviser suggested today that sanctions & protests have Iran 'choked off', will force them to negotiate. Actually, I couldn't care less if they negotiate. Will be totally up to them but, no nuclear weapons and 'don't kill your protesters'."
مشاور امنیت ملی امروز عنوان کرد كه تحریم ها و اعتراضات، ایران را«به شدت تحت فشار»قرار داده است و آنها را مجبور به مذاكره می كند.در واقع، اصلا برایم اهمیتی نداردکه آیا آنها مذاکره می کنند یا نه.این کاملاً به عهده ی خودشان است، اما سلاح هسته ای نداشته باشیدو«معترضان خود را نکشید.» https://t.co/DBGGs8QFcJ
— Donald J. Trump (@realDonaldTrump) January 13, 2020
Revolutionary Guard members patrolled on motorbikes while plainclothes security men were also out in force.
Members of Iran's Basij militia, which is affiliated with the Revolutionary Guards, gathered outside the British embassy, demanding it be closed, according to state media.
The British ambassador to Iran, Rob Macaire, earlier denied taking part in anti-government demonstrations after he was held by Iranian authorities during protests over the fatal plane crash.
"Can confirm I wasn't taking part in any demonstrations!" he tweeted. "Went to an event advertised as a vigil for victims of #PS752 tragedy. Normal to want to pay respects - some of victims were British. I left after 5 mins, when some started chanting."
Thanks for the many goodwill messages. Can confirm I wasn’t taking part in any demonstrations! Went to an event advertised as a vigil for victims of #PS752 tragedy. Normal to want to pay respects- some of victims were British. I left after 5 mins, when some started chanting.
— Rob Macaire (@HMATehran) January 12, 2020
He said he was arrested half an hour after leaving the area.
The crash on Wednesday killed everyone on board - mostly Iranians and Iranian-Canadians.
Canadian Prime Minister Justin Trudeau said it has been gut-wrenching to listen to stories from relatives of 57 Canadians who perished in the crash.
He added: "We will not rest until there are answers. We will not rest until there is justice and accountability."
Members of Canada's standing rapid deployment team arrived in Iran on Saturday to establish a base of operations for the Canadian government in the wake of the crash.
Iranian authorities admitted to accidentally shooting the plane down in the face of mounting evidence and accusations by Western leaders.
Iran had initially blamed the incident on a technical failure, insisting armed forces were not to blame.
However it downed the airliner as it braced for possible American retaliation after firing ballistic missiles at two bases in Iraq housing US forces.
The missile attack was a response to the killing of Major General Qassem Soleimani, Iran's top general, in a US airstrike in Baghdad.
