By Daria Sito-Sucic and Gordana Katana
BANJA LUKA, Bosnia (Reuters) - Thousands of Bosnian Serbs staged rival rallies for and against the government in the capital of Bosnia's autonomous Serb region on Saturday, kept apart by a heavy police presence after warnings of violence.
Authorities had banned both sides from marching through Banja Luka to avoid confrontations in the politically charged atmosphere in the build-up to local elections in October.
The opposition was protesting against what it sees as corruption and the poor state of the economy while the rival rally was a show of support for the government.
"We have to fight for our state," Serb Republic President Milorad Dodik told about 10,000 flag-waving supporters, some carrying pictures of Russian President Vladimir Putin. "We want peace. Today we defend our republic from treason."
Among Dodik's supporters was Darko Mladic, son of the Bosnian Serb wartime military leader Ratko Mladic who is facing war crimes charges at The Hague.
Across town, a similar number of opposition protesters waved anti-Dodik banners saying: "This is not Sicily, we have had enough of Godfathers". They demanded early parliamentary elections, economic reforms and the investigation of what they called political murders and corruption cases.
The opposition rally was addressed by Sonja Karadzic, daughter of former Bosnian Serb political leader Radovan Karadzic, who was jailed in March for genocide.
Worried that unrest in Bosnia could destabilise his own country, Serbian Prime Minister Aleksandar Vucic had urged Bosnian Serb politicians to prevent the protests turning violent.
But police kept the demonstrators apart with metal barriers and city-centre cafes and shops were closed. The rallies ended peacefully.
Political tensions in the Serb Republic have risen since elections in 2014, when Dodik's ruling party lost its place in the Bosnian government to the Alliance for Change, a pro-Europe reformist group, and remained in control only of the Serb Republic government.
Dodik, who favours closer ties with Russia and has threatened to pull his region out of Bosnia's complex state structure, says officials who support a reform agenda designed to bring Bosnia closer to the European Union are traitors.
The opposition accuses Dodik of autocracy and corruption. He has been investigated for embezzlement and abuse of office but never charged.
Since coming to power with Western backing 10 years ago, Dodik has adopted nationalist policies aimed at increasing his region's autonomy and weakening state institutions by blocking laws in Bosnia's national parliament.
After Bosnia's 1992-95 war, the country was split into a Serb Republic and a Federation of Muslim Bosniaks and Catholic Croats, linked via weak central government.
(Additional reporting by Maja Zuvela; Writing by Daria Sito-Sucic; Editing by Tom Heneghan)