Serbian authorities have blamed the pro-democracy student movement Odpor (Resistance) for allegedly shooting at a supporter of the regime of Slobodan Milosevic.
Odpor's spokesmen, however, deny the allegations and say
associates of the president's son, Marko Milosevic, were responsible.
Odpor spokesman Vukasin Petrovic said Odpor had used non-violent methods of protest. He said this was "the only
legitimate method of political struggle".
Mr Petrovic said the shooting of Milan Lazic, 19, a member of the Yugoslav United Left party (JUL), in a bar in Pozarevac, was part of a build-up of violence against Odpor.
The official Yugoslav news agency Tanjug carried a statement by Ivan Markovic, directorate secretary of the JUL. He said that a group of "hooligans" wearing Odpor symbols attacked a group of young JUL supporters in a bar, firing at Milan Lazic and hitting his brother, Sasa Lazic, over the head with a pistol butt.
The hooligans were allegedly led by Radojko Lukovic, who is over 40 years of age (presumably exceptionally old to be a student), assisted by Momcilo Veljkovic, "a notorious local criminal and psychiatric case".
Mr Markovic described Odpor as "a typical Hitlerjugend militant organisation, the only difference being that it does not have the ideology and age of fascist youth. Their ideology is American money, and age does not matter to them," he said.
Odpor's version of the incident identifies the victim Lazic and some other members of the JUL - all close friends of Marko Milosevic, son of the Yugoslav president - as the aggressors, claiming they were bullying an Odpor member, Dragan Milanovic, in an attempt to intimidate him into resigning from Odpor.
Odpor said that earlier that day, Mr Milanovic had been "beaten up round the whole city" by JUL youths, who ordered him to come back to the bar with a written resignation from Odpor. They allegedly threatened that if he did not they would kill him and "cut his stomach out".
Mr Milanovic was terrified to defy them by not returning to the bar and asked the police for protection. The police, however, would not accompany him. Instead, two fellow Odpor members went with him.
When they reached the bar, claimed Odpor, they were attacked by ten or so persons wielding sawn-off shotguns, identified as employees of Marko Milosevic's company Madonna. They attacked and beat up the Odpor activists, and also lawyer Nebojsa Sokolovic, who happened to be passing at the time.
Sasa Lazic drew a gun; Veljkovic, the "psychiatric case", managed to grab it, and in self-defence, hit Sasa Lazic with the butt.
At this point, the police arrived and arrested the Odpor activists and Mr Sokolovic on charges of attempted murder of the Lazic brothers.
All three detainees were injured in the fight, Radojko Lukovic so severely that he had to be transferred to an emergency centre in Belgrade.
According to Mr Petrovic, the incident is the climax of a campaign against Odpor activists in Pozarevac that had been going on since a local committee of the movement was formed there, and which has escalated over the past month.
He said there had been a number of incidents of Marko Milosevic and his cronies threatening and assaulting Odpor activists.
"They would put a gun in their mouths or threaten them with a chainsaw," Mr Petrovic said.
He called on the police and "all responsible state institutions" to establish the truth about the incident.
The Yugoslav Committee of Lawyers for Human Rights has sent representatives to Pozarevac, and local opposition parties have set up a crisis headquarters.