DONETSK, February 15 (RIA Novosti) – Ukrainian investigators are not ruling out the possibility that a terror attack caused the crash of an Antonov An-24 turboprop airliner at Donetsk Airport on February 13, Deputy Prosecutor General Viktor Voitsishen said on Friday.

“A terror attack is being considered as a possible cause,” Voitsishen told journalists, adding that pilot error and weather conditions are among other possible causes of the accident.

The plane, carrying soccer fans headed for a match against a German team, missed the runway in the eastern Ukrainian city of Donetsk on Wednesday evening, turned upside down, broke into pieces and caught fire. Of the 52 people onboard, five died and nine others 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, adding 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, the SBU.

The crashed An-24 had a user's operating certificate valid until April 5, 2013, Porodko said.

A panel led by Ukrainian Deputy Prime Minister Oleksandr Vilkul is analyzing the aircraft's flight data recorders. A full investigation into the crash could take a month, but the panel "will try to provide its conclusions sooner," Vilkul told reporters on Thursday.