Tehran, Jan 10 (IANS): Iran on Friday urged all the parties involved to contribute to a probe into the crash of a Ukrainian airliner which killed all the 176 people on board shortly after taking off from Tehran two days ago.

"According to international regulations, representatives from the civil aviation agency of the country where the crash has taken place (Iran), the civil aviation agency of the country which has issued the airworthiness certificate (Ukraine), the owner of the airliner (Ukraine International Airlines), the aircraft manufacturer (Boeing), and the jet engine manufacturer (CFM International) can participate in the investigation process," Ali Rabiei, spokesman for the Iranian administration, said.

Rabiei also said that a delegation from Ukraine was already in Iran, and Tehran has called on Boeing to dispatch its own representative to participate in the process of reading the black box data.

Iran has also invited the US National Transportation Safety Board (NTSB) to take part in the investigation.

The NTSB announced it would join the probe into the crash and has designated an accredited representative.

Boeing said on Wednesday that it was ready to provide any necessary assistance, while the International Civil Aviation Organization (ICAO) also pledged to assist the probe into the crash.

Friday's development comes Canadian Prime Minister Justin Trudeau said on Thursday that intelligence indicated that Ukraine International Airlines (UIA) flight PS752 was shot down by an Iranian missile on Wednesday.

"We have intelligence from multiple sources, including our allies and our own intelligence. The evidence indicates that the plane was shot down by an Iranian surface-to-air missile. This may well have been unintentional," Trudeau told the media.

But Iranian spokesman Rabiei denied the claim, saying "these reports are a psychological warfare against Iran ... all those countries whose citizens were aboard the plane can send representatives and we urge Boeing to send its representative to join the process of investigating the black box".

Sixty-three Canadians were aboard the UIA flight PS752.

Trudeau's remark followed US media reports that said the airliner was was mistakenly shot down by Iran.

In separate reports, CBS News and Newsweek said US and Iraqi intelligence officials were confident the Ukrainian plane was brought down by a missile fired by Iran.