A small plane carrying a group of skydivers burst into flames and crashed in a field in northwestern Bosnia-Herzegovina on Sunday afternoon, killing all five people on board, police said.

The accident happened moments after the Cessna 182 aircraft took off from Zalužani Airport in Banja Luka, a major city in the Bosanska Krajina region of Bosnia-Herzegovina. It was carrying a pilot, a parachuting instructor and three people who were undergoing parachuting training.

Police and witnesses said family members of some of the victims watched in horror as the small sports plane suddenly burst into flames moments after take-off. The aircraft, which was owned by Parachute Club Banja Luka, then crashed into a field close to the small airport where it was engulfed in flames.

It was not immediately clear what caused the accident, but Republika Srpska Interior Minister Stanislav Cado pledged a full investigation to avoid similar accidents in the future. Republika Srpska is one of the two main political entities of Bosnia-Herzegovina, with the other being the Federation of Bosnia and Herzegovina.

"With great sadness I received the news today of the sports plane which crashed at Zalužani and claimed the lives of five young people," said Aleksandar Džombić, the prime minister of Republika Srpska. He offered his deepest condolences to the families on behalf of his government.

Sunday's accident is the worst aviation accident in Bosnia-Herzegovina since a helicopter belonging to the European Union Force Althea (EUFOR) crashed in a mountainous area near Travnik in June 2008, killing two Spanish EUFOR pilots and two German EUFOR personnel.

Prior to that, in February 2004, Macedonian President Boris Trajkovski was among nine people killed when his plane crashed during stormy weather into a mountainside in southeastern Bosnia-Herzegovina, not far from Mostar International Airport. There were no survivors in the crash, which is believed to have been caused by pilot error.