Iran’s judiciary says arrests have been made over the shooting down of a Ukrainian plane that killed 176 people.

It came as the country’s president called for a special court to be set up to probe the downing last week of the passenger jet by Iranian forces just after take-off from Tehran, killing all onboard.

A judiciary spokesman said: “Extensive investigations have taken place and some individuals are arrested.”

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He did not say how many individuals have been detained or name them.

Iran, which initially dismissed allegations that a missile had brought down the jetliner, acknowledged three days after the incident on Wednesday that its Revolutionary Guard had shot down the Ukrainian plane by mistake, amid mounting evidence.

President Hassan Rouhani said in a speech televised in Iran on Tuesday: “This is not an ordinary case.

“The entire the world will be watching this court.”

The announcement came amid a surge of anger and protests by Iranians in recent days over the tragedy and apparent attempts by senior officials in Iran to cover up its cause.

Mr Rouhani also called for a special court to be set up to probe the incident.

He called the incident “a painful and unforgivable” mistake and promised that his administration would pursue the case “by all means”.

The president said: “The responsibility falls on more than just one person,” adding that those found culpable “should be punished”.

“There are others, too, and I want that this issue is expressed honestly,” he said, without elaborating.

Iran shot down the plane as its forces were on alert for possible US retaliation after Iran launched ballistic missiles on two military bases housing US troops in Iraq.

No-one was hurt in that attack, which was carried out in response to the killing of Revolutionary Guard general Qassem Soleimani in an American air strike in Baghdad.

While Mr Rouhani pointed to mistakes and negligence, he also repeated the government’s line that the tragedy was ultimately rooted in US aggression.

He said: “It was the US that made for an agitated environment. It was the US that created an unusual situation. It was the US that threatened and took our beloved (Soleimani),” he said.

Mr Rouhani called the government’s admission that Iranian forces shot down the plane a “first good step”.

He added that Iranian experts who retrieved the Ukrainian plane’s flight recorder, the so-called black box, have sent it to France for analysis.

The plane, en route to the Ukrainian capital of Kyiv, was carrying 167 passengers and nine crew members from several countries, including 82 Iranians, 57 Canadians – including many Iranians with dual citizenship – and 11 Ukrainians, according to officials.

There were several children among the passengers, including an infant.

General Amir Ali Hajizadeh, the head of the Guard’s aerospace division, said over the weekend his unit accepts full responsibility for the incident. He said when he learned about the downing of the plane: “I wished I was dead.”

The incident raised questions about why Iran did not shut down its international airport or airspace the day it was on alert for US military retaliation.

The shooting down of the plane and the lack of transparency around it has reignited anger in Iran at the country’s leadership.

Online videos appeared to show security forces firing live ammunition and tear gas to disperse protests in the streets.

Iran’s judiciary has also said that 30 people had been detained in the protests.

An Iranian film director who had called for protests in Tehran’s Azadi, or Freedom, Square is among those who were held then released.

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Iranian authorities briefly arrested British Ambassador Rob Macaire on Saturday evening. He said he went to a candlelight vigil to pay his respects for the victims of the Ukrainian plane incident and left as soon as the chanting began and it turned into a protest.

Iran’s foreign ministry summoned the British ambassador on Sunday to protest over what it said was his presence at an illegal protest.

The UK, in turn, summoned Iran’s ambassador on Monday “to convey our strong objections” over the weekend arrest.