BELGRADE (Reuters) - Serbia’s Prime Minister Aleksandar Vucic warned on Friday against resurgent nationalist rhetoric in the region a day after the U.N. war crimes tribunal acquitted Serbian chauvinist firebrand Vojislav Seselj.

Serbian nationalist leader Vojislav Seselj speaks during a news conference in his Radical party headquarters in Belgrade, Serbia, March 31, 2016. REUTERS/Stringer

Vucic, once a close Seselj ally and part of his defense team in The Hague who broke with him in 2008 and turned pro-European, said Seselj’s policies would damage Serbia and its bid for European Union membership.

After a marathon trial, the Hague court on Thursday cleared the 61-year-old Seselj, head of the ultra-nationalist Serbian Radical Party, of charges of fomenting ethnic hatred in the 1990s Yugoslav wars that killed 130,000 people.

His acquittal caused dismay among victims and wartime foes of the Serbs in the former Yugoslav republics and sparked jubilant celebrations by his backers, including in the eastern Bosnian town of Srebrenica, scene of a 1995 genocide.

“Such policies are pushing Serbia back to the past, to instability, torments and economic hardships. Such policies would isolate us from everyone in the Balkans and in Europe as well,” Vucic told a news conference.

“Nationalist forces are in resurgence everywhere (and) I will fight that with every democratic means,” he said, adding that he had a clear conscience over his past.

An alliance led by Vucic’s Progressives has 135 deputies in the 250-seat parliament and leads a ruling coalition together with several smaller parties, including the Socialist Party of Serbia once led by former President Slobodan Milosevic.

Some analysts said Seselj’s acquittal could give a boost to his Radical Party in Serbia’s April 24 elections, but they expect ultra-nationalists to win only small number of seats at best and say they will not challenge Vucic’s grip on power.

However, Vucic stressed the challenge his party faced, saying an unspecified opinion poll showed it may not be able to form a coalition government after April 24.

“We are never closer to a election defeat, it is very real ... It is for the people to decide,” he said.

Jovo Bakic, a sociologist at the University of Belgrade, said Vucic’s comments were intended to rally his supporters.

“Seselj cannot endanger Vucic, though his acquittal could blow some wind into the sails of the Radicals ... this is (Vucic’s) way of mobilizing his own electorate,” Bakic said.