A wartime commander of Bosnian Croat forces alarmed an international war crimes appeal hearing when he claimed to drink poison when his conviction was upheld.

Slobodan Praljak, who was sentenced to 20 years in jail in 2013 for crimes in the Bosnian war, shouted: "I am not a war criminal" and drank from a bottle moments after the judges at the International Criminal Tribunal for the Former Yugoslavia (ICTY) confirmed his sentence.

The hearing was suspended when his lawyer told the court: "My client says he has taken poison".

The condition of the 72-year-old is unclear. He was taken by medical services for treatment.

Praljak, who gained three university degrees in electrical engineering, philosophy and film, worked as a director of theatres for several years before joining the Croatian army.

Former Croation president Franjo Tudjman appointed him as one of 14 members of the Republic of Croatia's Council of National Defence in September 1992.

He also held other positions in the Croatian army, including assistant minister of defence and senior representative of the Croatian Ministry of Defence to the Herceg-Bosnia/HOV government and armed forces.

He put Tudjman's instructions into action and conducted operations to force out Muslims to create a Croatian mini-state in Bosnia.

He was said to have failed to make any effort to stop the rounding up of Muslims in Prozor during summer 1993 or attacks on mosques and other properties in the city of Mostar.

It was alleged that he played a prominent role in securing weapons and ammunition for the Bosnian Croat defence forces (HVO) during the Bosnian war between 1992 and 1995.

He was also charged with ordering the destruction of Mostar's 16th-century bridge in November 1993. Judges said that "caused disproportionate damage to the Muslim civilian population".

He appeared in the court along with five other high-level politicians and defence officials who were convicted of the ethnic cleansing of Bosnian Muslims during the war.

All had their sentences upheld, although several convictions for specific crimes were reversed on appeal.