Sudanese investigators are trying to determine what caused a jetliner that had just landed in a thunderstorm to veer off a runway and burst into flames in Sudan's capital.

At least 29 people were killed inside the burning plane, while 171 managed to escape, said Sudan Civil Aviation Authority spokesman Abdel Hafez Abdel Rahim Mahmoud, adding that 14 still remained unaccounted for. Many passengers fleeing the burning plane did bother to pass through customs, making the toll initially difficult to ascertain.

Civil defence officials are examining the wreckage to determine the causes of the crash, police spokesman Major General Mohammed Abdel Majid al-Tayeb told the official SUNA news agency.

The Sudan Airways jetliner appeared to have gone off the runway after landing at Khartoum International Airport, and several loud explosions resounded as fire raced through the aircraft.

The roaring blaze dwarfed the Airbus A310's shattered fuselage as firefighters sprayed water, Sudanese TV footage showed.

One survivor said the landing was "rough," and there was a sharp impact several minutes later. "The right wing was on fire," said the passenger, who did not give his name. He said smoke got into the cockpit and some people started opening the emergency exits. Soon, fire engulfed the plane, he told Sudanese television.

There were differing reports on the role weather played. The head of Sudanese police, Mohammad Najib, said bad weather "caused the plane to crash land, split into two and catch fire."

Youssef Ibrahim, director of the Khartoum airport, disputed that bad weather was to blame and told Sudanese TV that the plane "landed safely" and the pilot was talking to the control tower and getting further instructions when the accident occurred.

"One of the (plane's) engines exploded and the plane caught fire," Ibrahim said. He blamed the accident on technical problems, but didn't elaborate.

Airbus said in a statement that it was sending a team of specialists to Khartoum to help in the investigation. It said the plane involved in the accident was 18 years old and had been operated by Sudan Airways since September.