Bishkek: Kyrgyzstan announced a national day of mourning today after 65 people died at the weekend in one of the tiny Central Asian state's worst air disasters.

Russia was to send air crash experts to the former Soviet state, independent since 1991, to help examine the flight data recorders for clues as to why the Tehran-bound Boeing 737-200 crashed late on Sunday.

"This is the worst air disaster in recent years. We have never faced such a tragedy," said Health Ministry spokeswoman Yelena Bayalinova.

Engulfed by fireball

The Kyrgyz government ruled out an act of terrorism.

Survivors said a fireball engulfed the plane when it came down near Bishkek's main airport at Manas, some 30km from the Kyrgyz capital.

Ali Khozemi, 39, a businessman from Tehran who was flying with his two sisters, said scorching heat built up inside the plane after the crash. "At one moment we could not breathe at all because our lungs were burning," he said. "We were praying to Allah and waiting to die."

More than 100 people gathered at Bishkek city morgue to identify the bodies of their relatives or friends.

Zumrat, a woman in her 30s, said she could not find her son's body: "I am still not convinced he is dead, although he is not among the survivors" listed by officials.

Photographs from the crash site released by the state news agency Kabar showed the plane's smoking fuselage and fragments of aircraft strewn over the ground.

Airport employees who saw the wreckage on Sunday said the tail was the only part of the plane still intact.