Iran’s judiciary on Tuesday said arrests have been made over the downing last week of a Ukrainian passenger by Iranian forces just after takeoff from Tehran, killing all 176 people aboard.

“Extensive investigations have taken place and some individuals are arrested,” the judiciary spokesperson, Gholamhossein Esmaili, said on Tuesday. He was quoted by Iranian state media, but did not say how many individuals have been detained or name them.

The Revolutionary Guards' aerospace commander Brigadier General Amirali Hajizadeh accepted full responsibility but said the missile operator who opened fire had been acting independently.

"Numerous investigations have been conducted in this area and every night our judicial team has been seeking documents until midnight," said Esmaili, adding: "Suggestions have been made so far but we have to weigh all the dimensions to get to the truth."

Earlier on Tuesday, Iran’s president had called for a special court to be set up to probe the shootdown of the Ukrainian plane.

Iran, which initially dismissed allegations that a missile had brought down the jetliner, acknowledged — three days after Wednesday’s downing and in the face of mounting evidence — that its Revolutionary Guard had shot down the Ukrainian plane by mistake.

“The judiciary should form a special court with a ranking judge and dozens of experts,” 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.”

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

“The responsibility falls on more than just one person,” he said, 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.

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

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.

Iran shot down the plane when it was bracing for possible US retaliation for a ballistic missile attack on two military bases housing US troops in Iraq. No one was hurt in that attack, which was carried out to avenge the stunning killing of Revolutionary Guard General Qasem Soleimani in an American airstrike in Baghdad.

The shootdown and the lack of transparency around it has reignited anger in Iran at the country’s leadership, with protesters taking to the streets in past days.