Three Britons have died after a Ukrainian passenger plane crashed moments after take off from Iran, officials in Kyiv have confirmed.
All 176 people on board the Ukraine International Airlines Boeing 737 flight from Imam Khomeini International Airport in Tehran to Kyiv were killed.
The plane disappeared from radar just a "few minutes" after taking off this morning, Ukraine International Airlines (UIA) said.
Iranian state television said the crash was caused by mechanical issues.
Qassem Biniaz, a spokesman for Iran's Road and Transportation Ministry, said it appeared that a fire had started in one of the plane's engines.
The pilot then lost control of the plane, sending it crashing into the ground, Mr Biniaz told the state-run IRNA news agency.
Some 82 Iranians, 63 Canadians, 11 people from the Ukraine, nine of whom were crew members, 10 Swedes, four Afghans and three Germans were on board the flight along with three Britons, Ukrainian Foreign Minister Vadym Prystaiko said.
Rescue crews said they did not expect to find survivors in the wreckage, and UIA said it had suspended flights to Tehran until further notice.
A spokesman said: "The airline expresses its deepest condolences to the families of the victims of the air crash and will do everything possible to support the relatives of the victims."
The airline said the aircraft was a 737-800, built in 2016.
A number of 737-800 models have been involved in deadly accidents over the years.