BELGRADE (AFP) - Some 10,000 supporters of the Serb ultranationalist Vojislav Seselj, released by a UN war crimes court for cancer therapy, joined him Saturday at a rally in protest at his country's shift towards Europe.

The gathering was seen as a test of Seselj's influence at home, where he returned this week after almost 12 years in detention at the court in The Hague, yet to issue a verdict in his trial for crimes during the Balkan wars of the 1990s.

"Serbia has to decide should it go towards the East (Russia) or towards the West, where all its enemies are," the 60-year-old firebrand told a euphoric crowd in downtown Belgrade.

"We will not wait for the end of this government's mandate. Already next year we will have elections that the Serb Radical Party (SRS) will win," Seselj vowed from the stage.

Waving the flags of Serbia and Russia, the Balkan country's traditional ally, his supporters carried portraits of President Vladimir Putin and the last Russian Emperor Nicholas II and banners reading "No to EU and Nato".

Serbia opened membership talks with the European Union this year.

Seselj has vowed to unseat from power his former closest collaborators - President Tomislav Nikolic and Prime Minister Aleksandar Vucic - who both left his party in 2008 and founded their own pro-European SNS movement.

Immediately upon his arrival in Belgrade, Seselj labelled the two "traitors" who "sold our honour and gave up Serb nationalism to become servants of the West".

"He will liberate us from those pro-European bootlickers," Petar Radojkovic, a 47-year-old construction worker who joined the rally told AFP, in a reference to the government.

Milanka Stupljanin, a 29-year-old saleswoman, said the ultranationalist was the "only one who can revive Serbia".

To achieve his aims, Seselj said he planned to "revitalise and reorganise" his Serb Radical Party (SRS) and attract new members among "all those who are dissatisfied".

NINE COUNTS INCLUDING MURDER

"We should turn towards Russia. Joining the European Union would be a real disaster for Serbian people," he said.

"However, we do not want a conflict with the EU; if the Union accepts to cooperate with us on equal grounds, why not?"

But Seselj has returned to a country that has greatly changed since he voluntarily surrendered to the International Criminal Tribunal for the former Yugoslavia (ICTY) in 2003, going on trial four years later.

The groups which once helped whip up murderous fervour as the former Yugoslavia disintegrated in the 1990s are on a steady slide into oblivion.

Today, none are even represented in the Serbian parliament, including Seselj's party.

Political analyst Dusan Janjic was expecting more people at Saturday's rally "since the radical (Seselj's) party is a well organised grouping".

But the "public clearly did not show much interest for Seselj's comeback. Serbia changed a lot during his absence," he told AFP.

His return will not threaten the government, agreed the analyst Djordje Vukadinovic.

"To topple the government is too ambitious a goal, especially if he does not change the rhetoric he has been using in the 1990s," he said.

Seselj is accused of leading ethnic Serb volunteers in persecuting Croats, Muslims and other non-Serbs during the brutal 1990s wars in Croatia and Bosnia.

His trial wrapped up in March 2012, with a verdict still to be handed down.

During the trial, Seselj pleaded not guilty to nine counts including murder, torture, cruel treatment and wanton destruction of villages.

Seselj's return has sparked outrage among victims' groups in neighbouring Croatia and Bosnia.

On Saturday, Croatian Foreign Minister Vesna Pusic said she could only "voice condolences to Serbia for having a mad war criminal on its streets, instead of him being where he was and where he should have remained", referring to the UN tribunal.