BEIRUT, Lebanon  A Russian-built Iranian passenger plane bound for Armenia from Tehran crashed and exploded in a fuel-laden fireball minutes after takeoff early Wednesday. All 168 people aboard were killed, Iran’s state news media said.

The airline crash is Iran’s worst in six years, and it underscored the country’s vulnerability to aviation disasters. Iran has been unable to adequately maintain its aging fleet of American-built aircraft for 30 years because of an embargo after the Islamic Revolution, and has increasingly relied on aircraft from Russian manufacturers, which have their own troubled safety history.

The plane that crashed Wednesday, a Tupolev 154 leased by Caspian Airlines, based in Tehran, was bound for Yerevan, the Armenian capital, with 153 passengers and 15 crew members, and was loaded with fuel, Iranian news services said. It went down in a farm field near Qazvin, a city about 75 miles from Tehran, said the Qazvin police chief, Hussein Behzadpour, in comments to Iran’s English-language Press TV.

Witnesses quoted by Press TV and other Iranian news agencies said that the tail and at least one of the tail engines were on fire as the plane plummeted, and that it exploded in flames on impact, creating a crater 30 feet deep and scattering body parts and wreckage.

Image The jet crashed 16 minutes after taking off from Tehran. Credit... The New York Times

Television images from the scene showed smoking ruins and emergency workers rummaging through the wreckage, presumably looking for the “black box” flight recorders that would reveal the crew’s conversations and the plane’s speed, altitude and heading.

The spokesman for the Aviation Organization in Iran, Reza Jafarzadeh, said the plane, Flight 7908, crashed 16 minutes after departing from Imam Khomeini Airport in Tehran, according to Press TV.

Sirous Saberi, deputy governor of Qazvin Province, said the plane had a technical problem shortly after takeoff and was trying to return to the airport in Tehran, according to the Mehr News Agency in Iran.

Six Armenian citizens and two Georgian citizens were on the flight, and the rest were probably Iranians, The Associated Press reported, citing the deputy chairman of Armenia’s civil aviation authority in Yerevan. The passengers included eight members of Iran’s national youth judo team, two coaches and a delegation chief, en route to train with the Armenian judo team and attend a competition in Hungary in August, the semiofficial Iranian Labor News Agency said.

The leader of the disaster management center in Iran’s Health Ministry said that all aboard had been confirmed dead, state news agencies said.

It was the first fatal accident for Caspian Airlines, which was founded in 1992. The airline operates a fleet of six TU-154 airliners, all dating from the mid-1980s to the early 1990s.

Image The scene of a plane crash on Wednesday, near Qazvin, Iran, about 75 miles from Tehran. Credit... Sina Shiri/ISNA, via Associated Press

The aircraft that crashed Wednesday was built in 1986 and was leased to Caspian in 1998. It is believed to be owned by VARZ-400, a Russian aircraft maintenance and overhauling company, according to Ascend, an aviation industry consulting company based in London.

The crash was Iran’s deadliest since February 2003, when a Russian-built Ilyushin plane carrying 289 Iranian soldiers slammed into a mountain in southeast Iran moments before it was to land.

Many of Iran’s deadliest air disasters have involved its fleet of Russian planes designed and built during Soviet times. In 2006, a TU-154 operated by Iran Airtour burst into flames upon landing in Tehran, killing 29 of the 148 people aboard. Airtour, affiliated with Iran’s national carrier, also suffered a fatal accident in 2002, when a Tupolev jet plowed into a mountainside, killing all 119 aboard.

Since entering service in 1971, the TU-154 has been in 54 crashes, resulting in the deaths of 2,602 passengers and 258 crew members, according to Ascend.

In 2005, a Lockheed C-130 operated by the Iranian military rammed into a housing complex shortly after takeoff from Mehrabad Airport in Tehran, killing 115 people, including 21 on the ground.

Caspian Airlines passed an operational safety audit in 2007 by the International Air Transport Association. The airline is scheduled to seek renewal of its safety certification by the end of November.