Moscow, Feb 16 (IANS/RIA Novosti): Ukrainian investigators are not ruling out the possibility that a terror attack may have caused the crashlanding of a plane in the eastern city of Donetsk, which killed five people.

The Antonov An-24 turboprop airliner crashlanded at Donetsk airport Feb 13.

Deputy Prosecutor General Viktor Voitsishen said: "A terror attack is being considered as a possible cause."

He said pilot error and weather conditions were among other possible causes of the accident.

The plane, carrying soccer fans for a match against a German team, missed the runway, turned upside down, broke into pieces and caught fire.

Of the 52 people onboard, five died and nine were seriously injured.

"We should check all the possibilities, including this one (terror attack), because some passengers were not registered for the flight," Voitsishen said.

He said three people boarded the plane without registration.

Investigators are checking whether flammable or explosive items were onboard the plane, said Volodymyr Porodko, deputy chairman of Ukraine's security service SBU.

The crashed An-24 had a user's operating certificate valid until April 5, Porodko said.

A panel led by Ukrainian Deputy Prime Minister Oleksandr Vilkul is analysing the aircraft's flight data recorders.