Quote:Slobodan Praljak, 72, was one of six former Bosnian Croat political and military leaders up before the court.
He was sentenced to 20 years' imprisonment in 2013 for crimes in the city of Mostar.
On hearing that his sentence had been upheld, he told the judge, "I have taken poison".
The six were attending the final appeals judgment to be handed down by the UN's International Criminal Tribunal for the former Yugoslavia (ICTY).
Though allies against the Bosnian Serbs in the 1992-95 war, Bosnian Croats and Muslims also fought each other for a period of 11 months, with Mostar seeing some of the fiercest fighting.'Don't take away the glass'
Praljak stood and raised his hand to his mouth, tipped his head back and appeared to swallow a glass of liquid.
Presiding judge Carmel Agius immediately suspended the proceedings and an ambulance was called.
"Okay," the judge said. "We suspend the... We suspend... Please, the curtains. Don't take away the glass that he used when he drank something."
Before the curtains were lowered, the courtroom could be seen in a state of confusion, the BBC's Anna Holligan reports from The Hague.
An ambulance could later be seen arriving outside the tribunal while a helicopter hovered above the scene.
Several emergency rescue workers also rushed into the building carrying equipment in backpacks.
More than an hour after the incident, a court guard told Reuters news agency said Praljak was still "being treated".