A Ukrainian aircraft carrying 176 passengers crashed near Tehran shortly after take-off on Wednesday morning, AP reported, citing state-owned news outlets. All aboard the flight were killed, an Iranian emergency official said. There were 82 Iranians and 63 Canadians on the plane, officials said, adding that nine of the 176 people on board were crew members.

An investigation team was at the site of the crash, the government said. The plane had taken off from Imam Khomeini International Airport and is believed to have crashed due to mechanical problems.

Iranian search and rescue teams recovered the black boxes, AFP reported quoting Iran’s ISNA news agency. “The two black boxes of the Ukrainian 737 aeroplane that crashed this morning have been found,” said Reza Jafarzadeh, the spokesperson for the Iranian civil aviation authority.

Iranian emergency officer Pir Hossein Kulivand confirmed there were no survivors in the crash, and said that rescuers were now trying to collect the bodies.

“After taking off from Imam Khomeini international airport it crashed between Parand and Shahriar,” civil aviation spokesman Reza Jafarzadeh was quoted as saying. “An investigation team from the national aviation department was dispatched to the location after the news was announced.”

According to aircraft tracking website FlightRadar24, the Boeing 737-800 stopped sending data almost immediately after taking off. “We are aware of the media reports out of Iran and we are gathering more information,” tweeted The Boeing Company.

Ukrainian President Volodymyr Zelensky warned against speculation about the crash, according to AFP. “I ask everyone to keep from speculating and putting forth unconfirmed theories about the crash,” he said. Earlier in the day, he had ordered an investigation into the incident. Zelensky also directed a full evaluation of all civilian aircraft in the country.

In a statement, Ukraine International Airlines said the aircraft had been checked just two days before it crashed. The carrier also said it had decided to suspend flights to Tehran until further notice. The airline said it was doing “everything possible” to find out the reasons for the crash.

The Ukrainian Embassy in Tehran said the crash was due to an engine problem and ruled out an “act of terror” for the moment.

Aviation expert Stephen Wright also dismissed speculation that the plane was shot down by an Iranian missile. “There is a lot of speculation at the moment it has been shot down - I think that is not going to be the case at all,” he said. “The aircraft was climbing... it was going up in the right direction, which means that something catastrophic has happened. It could be a bomb or it could be some sort of catastrophic breakup of the aircraft.”

Air India temporarily reroutes flights

Meanwhile, Air India said it was temporarily rerouting its flights, and that of its subsidiary Air India Express, from Iranian airspace, PTI reported. “In light of the tensions within the Iranian airspace a decision to temporarily reroute flights of Air India and Air India Express overflying Iran has been taken,” an Air India spokesperson said. “This may lead to increase in flying time by approximately 20 minutes for flights from Delhi and 30 to 40 minutes for flights from Mumbai.”

Earlier in the day, the Directorate General of Civil Aviation had asked all Indian airlines to remain vigilant and take all precautions while flying over Iran, Iraq, Gulf of Oman and waters of the Persian Gulf.