A Ukrainian Boeing-737 carrying 176 people has crashed in Iran and officials say there is no chance of finding survivors.
Ukraine International Airlines flight PS752 to Kyiv went down after taking off from Imam Khomeini airport in Tehran at 06:12 local time (02:42 GMT).
The majority of passengers were from Iran and Canada.
Ukraine's Tehran embassy initially blamed engine failure but later removed the statement.
It said any comment regarding the cause of the accident prior to a commission's inquiry was not official.
Ukraine's president, Volodymyr Zelensky, warned against "speculation or unchecked theories regarding the catastrophe" until official reports were ready.
What is Iran saying?
Iranian media blamed technical problems and quoted an aviation official who said no emergency had been declared.
In a sign of the potential difficulties facing crash investigators, the head of Iran's civil aviation organisation was quoted as saying the Ukrainian plane's black box would not be handed over, either to Boeing or the Americans.
Ali Abedzadeh said "terrorism" had played no role in the crash, Iran's conservative Mehr news agency reported. Another official, Qasem Biniaz, blamed an engine fire. "Had the accident happened due to a missile strike, the plane would have exploded in the air," he told the IRNA news agency.
Debris and engine parts from the Boeing 737-800 NG plane were found some 10km (6 miles) from the airport and rescue workers with face masks searched the wreckage for victims.
Throughout the morning, Red Crescent workers laid out a long line of body bags.
Hours before the plane came down Iran carried out a ballistic missile attack on two air bases housing US forces in Iraq. There is no evidence that the two incidents were linked.
A series of airlines announced on Wednesday that they were avoiding both Iranian and Iraqi airspace.
Air France and KLM said they would use alternative routes while Lufthansa said it was also cancelling its daily flight to Tehran. Qantas, Air India, Japan Airlines, Singapore Airlines and Malaysia Airlines were among other airlines taking action.
Who was on board?
Among the victims were 82 Iranians, 63 Canadians, 11 Ukrainians including all nine crew, 10 Swedes, four Afghans, three Britons and three Germans, Ukrainian Foreign Minister Vadym Prystaiko said.
Ukrainian officials said that 169 people had bought tickets for the flight but two had not boarded the plane.
