The arrest is seen as hugely significant
Special forces in Serbia have arrested one of the country's most wanted war crimes suspects, former Yugoslav army colonel, Veselin Sljivancanin.
Mr Sljivancanin was picked up by police after a 10-hour standoff outside his Belgrade house following violent clashes with hardline supporters.
During the disturbances, vehicles were smashed and fires lit - and police then used tear gas and stun grenades to disperse them.
Veselin Sljivancanin is one of the so-called Vukovar Three accused of involvement in the massacre of more than 200 civilians in eastern Croatia in 1991.
He has been on the run since the fall from power of former Yugoslav leader Slobodan Milosevic three years ago.
Mr Sljivancanin had in the past threatened to blow himself up rather than hand himself over, but his wife reportedly said he had in the end "surrendered voluntarily".
Several hundred of Mr Sljivancanin's supporters attacked police who had to fire on the crowd to try to quell the disturbances.
Riot police were called in to disperse the crowd as vehicles were smashed and fires lit.
Civil disturbance on this scale has not been seen for many years on the streets of central Belgrade, says the BBC's Matthew Price in Belgrade.
Tension had been building all day in a small area of the city, close to the former colonel's home.
Police sealed off the area, then, after 10 hours, shortly before midnight local time, they battered down the armoured door of his flat and took their suspect into custody.
Mr Sljivancanin's two co-accused in the 1991 massacre in the Croatian town of Vukovar - one of the most notorious war crimes of Croatia's 1991-95 independence war - are already in detention at The Hague
US aid deadline
The arrest comes just before a 15 June deadline when the US Congress requires proof the Serbian authorities are co-operating with the Hague tribunal in order for a further tranche of economic aid worth $110 m to be released to Serbia.
According to Reuters news agency, a senior US official urged Belgrade last week to find Mr Sljivancanin, warning that certification would be a "difficult decision" if he was not in custody.
The latest arrest leaves former Bosnian Serb President Radovan Karadzic and army commander Ratko Mladic as the two remaining top fugitives indicted for war crimes during the break-up of Yugoslavia.