Kyrgyzstan has announced a national day of mourning for Tuesday after 65 people died 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.

Only 25 of the estimated 90 people aboard the aircraft, survived - 14 of them Kyrgyz nationals and 11 Iranians.

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

Survivors said a fireball engulfed the plane when it came down near Bishkek's main airport at Manas, some 20 miles 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.

He said: "At one moment we could not breathe at all because our lungs were burning.

"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)."

Flags will fly at half mast on public buildings on Tuesday and shows, theatres and cinemas will close for the day as a mark of respect for the dead, after President Kurmanbek Bakiyev ordered a day of national mourning.

The cause of the crash remained unclear, although Prime Minister Igor Chudinov said initial reports suggested the plane had suffered a sudden loss of cabin pressure, causing the pilot to request an emergency landing.

Members of a teenage basketball team were among the dead and officials said many of the victims were so badly burnt that DNA tests would be needed to identify them.

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