The footage, shot by French journalist Philippe Buffon, who posted it on YouTube, shows several young fighters hiding in a house on the front line in the suburbs of Sarajevo.

One is seen firing a sniper's rifle and boasting that he hit someone "in the head".

The images were broadcast on local TV and caused a huge stir in the Bosnian capital, where more than 11,000 people were killed during the 1992-95 siege, part of the bloody disintegration of Yugoslavia.

"A case was opened immediately after the video appeared on the web," the Bosnian war crimes prosecutor's office said in a statement.

"An investigation will be carried out into the circumstances and the role of all the people in the images."

Buffon's video, titled "The Snipers of Nedzarici" after a Sarajevo suburb, was no longer available on YouTube on Friday.

But some of the images including those of the shooting were included in a longer piece by Buffon seen by AFP.

Several media outlets claimed that the gunman was now a waiter in a cafe in a Bosnian Serb area of Sarajevo.

Hundreds have been convicted of crimes committed during a war that left 100,000 dead.

However, more than a quarter of a century after the conflict, local judiciary officials are still expected to deal with some 600 cases involving 4,500 suspects, according to official data.