The Ukrainian airliner that crashed outside Tehran on Wednesday killing over 170 people was a Boeing 737 built in 2016 and checked only two days before the accident, the company said.

"The plane was manufactured in 2016, it was received by the airline directly from the (Boeing) factory. The plane underwent its last planned technical maintenance on January 6, 2020," Ukraine International Airlines said in a statement.

It took off from Tehran airport at 6:10 a.m. and disappeared from radars just a few minutes later, crashing in Tehran province. 

There were no survivors among the crew and passengers, who were mostly Iranian and Canadian nationals, according to Ukraine's foreign ministry.

Cockpit and flight data recorders have been recovered but Iran said they would not be handed over to American company Boeing.  

Ukraine International Airlines, the country's biggest airline and privately owned, said it had "decided to suspend its flights to Tehran starting today" and until further notice.

It was notifying passengers' families and working with aviation authorities "to do everything possible to find the reasons for the aviation accident".

Preliminary statements by Iranian and Ukrainian authorities suggest the plane suffered an engine malfunction, though the airline did not detail any reasons for the accident.

Ukraine's president ordered an investigation into the crash and a sweeping check of "all civilian aircraft" in the country.