At least 39 people killed when an Iran-140 Sepahan Air passenger plane crashed after takeoff from Tehran's Mehrabad airport on a flight to Tabas in northeast Iran, state media reported.
Initial reports said that all of the 48 passengers and crew had been killed, but state media later reported that some passengers had been injured and transferred to hospital.
Islamic Republic News Agency (IRNA) said that eight or nine had survived and quoted a doctor as saying that one of the injured had regained consciousness.
Iran's airlines have been plagued by crashes, which Iranian politicians blame on international sanctions that block the airlines from replacing their ageing fleets. About 14 crashes involving Iranian planes were reported in the decade to January 2011.
President Hassan Rouhani ordered a halt to all flights of the Iran-140 pending full investigation, IRNA said.
The pilot detected technical issues four minutes after takeoff and tried to return to the airport, state television said, but the twin-engine turboprop crashed on a road at 9.18am local time. One eyewitness said the plane crashed into a wall.
State television said 37 people died instantly, two died on the way to hospital and nine others were undergoing medical treatment.
The Civil Aviation Authority said the passengers included two infants and three children under the age of 12, IRNA reported. Mashallah Shakibi, 63, a former member of parliament from Tabas was among the fatalities, according to reports from the Iranian state news channel IRINN.
One survivor said he was saved by jumping through a hole in the plane's body created by a blast. "The force of the blast threw us out of the plane," Mohammad Abedzadeh was quoted as saying on IRINN's website. "Seconds later, I saw the entire plane in flames," he said through tears.
A photograph on IRNA's website showed a huge plume of black smoke billowing over traffic standing at a road intersection. A photograph from the Iranian Student News Agency showed a charred tail fin lying on the ground.
The plane's black box was found according to IRNA reports. Authorities are investigating the cause of the crash.
For years, planes have been kept in service through parts imported on the black market, cannibalised from other planes or reproduced locally, aviation sources say.
Iran's four largest carriers – Iran Air, Iran Aseman Airlines, Mahan Air and Iran Air Tours – all have average fleet ages above 22 years, Iranian media have reported. They serve a market of 76 million people.
US companies Boeing Co and General Electric Co have said they are seeking to export parts to Iran under the agreement for sanctions relief.
The chief of Iran Air said the airline will need at least 100 passenger jets once sanctions against the country are lifted.
POOR SAFETY RECORD
The plane that crashed - an Iran-140 - is a locally assembled version of the Antonov-140. Its safety record has come into question in the past.
In December 2002, an Iran-140 test flight crashed, killing at least 46 people, including engineers who had helped design it. The government said human error caused the crash, but many expressed worries about the aircraft.
More than a dozen large airlines and several fledgling carriers operate in Iran. The state carrier, Iran Air, has a fleet of about 40 planes including nine Boeing 747 jets, some of which were built before the Islamic Revolution in 1979.
The safety record for the carriers has led to most Iranian flights being prevented from landing in the EU.
Mehrabad is located in a western suburb of Tehran and mainly functions as a domestic airport, although it also serves some international routes.