DUBAI, United Arab Emirates (AP) — Iran's president on Tuesday called for a special court to be set up to probe the downing last week of a Ukrainian passenger by Iranian forces just after takeoff from Tehran, killing all 176 people aboard.

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 U.S. retaliation for a ballistic missile attack on two military bases housing U.S. troops in Iraq. No one was hurt in that attack, which was carried out to avenge the stunning killing of Revolutionary Guard Gen. Qassem 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. Online videos appeared to show security forces firing live ammunition and tear gas to disperse protests in the streets.