A wartime commander of Bosnian Croat forces died after drinking poison during a hearing at the U.N. war crimes tribunal on Wednesday at which his 20-year prison sentence was upheld, Croatia's state TV said.

Slobodan Praljak, 72, drank from a bottle shortly after appeals judges confirmed his sentence for involvement in a campaign to drive Muslims out of a would-be Bosnian Croat ministate in Bosnia in the early 1990s.

"My client says he drank poison this morning," defense attorney Natasa Faveau-Ivanovic said.

"Slobodan Praljak is not a war criminal. I reject the verdict with contempt," the 72-year-old Praljak screamed, as he unscrewed a bottle he was holding and drank from it.

Presiding judge Carmel Agius suspended the hearing and called for a doctor.

"Courtroom one is now a crime scene," he said after confirmation that Praljak had died.

"Dutch [police] have already commenced an investigation," he added.

The ruling on some of the 22 counts for which the group was sentenced for up to 25 years in prison was still due to be read.

Bosnian Croat leaders Jadranko Prlic, 58, Praljak, Bruno Stojic, Milivoj Petkovic, Valentin Coric and Berislav Pusic were sentenced in the first instance in 2013. The Appeals Chamber overturned some of the counts.

It was the last judgment by the International Criminal Tribunal for the former Yugoslavia (ICTY), established by the United Nations in 1993, before it closes next month. The remaining work, including appeals in the genocide cases of Bosnian Serbs Radovan Karadzic and Ratko Mladic, will be handled by the UN Mechanism for International Criminal Tribunals (MICT).

Praljak was specifically charged with ordering the destruction of Mostar's 16th-century bridge in November 1993, which judges said "caused disproportionate damage to the Muslim civilian population".

A symbol of Bosnia's devastation in the war, the iconic Ottoman-era bridge was later rebuilt. But the city saw the worst of the Croat-Muslim clashes, with nearly 80 percent of the citytarget="_blank"'>