A Ukrainian airliner with 180 passengers and crew on board has crashed near Tehran's Imam Khomeini airport in Iran early on Wednesday.
Iran's state television said all those on board the airliner were killed.
According to the Iranian media, the Boeing 737-800 jet crashed near Parand, a suburb southwest of capital Tehran shortly after take-off.
Iran's Red Crescent earlier said there was no chance of finding survivors. Images posted on social media also indicated that there were no survivors.
According to Flighradar24 flight tracker, the Ukraine International Airline Flight 752 was scheduled to take off at 5:15am Tehran time heading to Boryspil International Airport in the Ukrainian capital of Kyiv.
The actual departure time was delayed for almost an hour at 6:12am.
A video posted by Iran's ISNA news agency showed a faint glow of light flickering in the dark shortly before a huge fireball was seen.
Photos posted online by ISNA also showed wreckage of the plane scattered all over the ground, as emergency personnel inspected the area.
"An investigation team from the national aviation department was dispatched to the location after the news was announced. We will give more reports in upcoming bulletins," Reza Jafarzadeh, spokesman of the Iranian Aviation Organisation told reporters in Tehran.
In a statement, Boeing said that it was "aware of the media reports" of the incident, and that it is "gathering more information."
The incident comes just hours after Iran launched a retaliatory attack on two US bases in Iraq.
The Boeing 737-800 is a very common single-aisle, twin-engine jetliner used for short to medium-range flights. Thousands of the planes are used by airlines around the world.
Introduced in the late 1990s, it is an older model than the Boeing 737 MAX, which has been grounded for nearly 10 months following two deadly crashes.
A number of 737-800 aircraft have been involved in deadly accidents over the years.
In March 2016, a FlyDubai 737-800 from Dubai crashed while trying to land at Rostov-on-Don airport in Russia, killing 62 onboard. Another 737-800 flight from Dubai, operated by Air India Express, crashed in May 2010 while trying to land in Mangalore, India, killing more than 150 onboard.
In recent years, Iran has seen several airline crashes.
In early 2019, a Boeing 707 military cargo plane crashed in bad weather west of the Iranian capital, killing 15 out of the 16 passengers.
In February 2018, an Iranian passenger plane with 65 people on board crashed during a flight from Tehran to Yasuj.
In 2014, an Antonov-140 type plane with 48 people on board crashed shortly after takeoff at Tehran's Mehrabad airport, leaving 39 people dead.