Thousands of supporters of Slovenia's bruised Prime Minister Janez Jansa took part in a show of force in the capital Ljubljana on Friday, hours before a planned counter-protest by his opponents.
Some 12,000 people, according to organisers, attended the rally in Ljubljana's central Congress Square. Police estimated there were about 9,000 present.
"We've been pushed to the point at which we will have to act firmly against this leftist fascism, against threats, violence and chaos," Jansa, attending a European Union summit in Brussels, told the flag-waving crowd in a pre-recorded speech.
"This is just the beginning, we will have to gather more often and show our strength."
Jansa is fighting to stay in office at the head of a government with just 36 seats in the 90-seat parliament after two parties withdrew from the coalition, the latest on Tuesday.
The two parties abandoned the centre-right Jansa after Slovenia's corruption watchdog levelled accusations of tax irregularities against the premier in January. A third party has also threatened to quit if Jansa does not resign.
Jansa, already on trial over an allegedly dodgy defence deal, has rejected the new accusations and said he intends to stay in office.
Jansa's lack of support in parliament makes it tough for him to implement austerity cuts and the deep structural reforms needed to pull the two-million-strong country out of recession.
Problems at Slovenia's banks, struggling under a mountain of bad debts, have raised speculation that the former Yugoslav republic, once a model newcomer to the European Union, may need a bailout.
A 52-year-old jobless demonstrator from Ljubljana, Irena, told AFP at the demo that she came to express her patriotic feelings and "for that Slovenia we got in the 1990s when we declared independence (from Yugoslavia)."
"I'm not a rightist, I'm a patriot, for Slovenia and for me and my children getting a job," she said, adding that she was afraid the situation in Slovenia was worsening "and could, horribly, end in a civil war."
Joze Krev, a 55-year-old hotel owner from the northern Slovenian region of Koroska, said he thought the corruption allegations against Jansa were politically motivated and that he was protesting "to show my patriotism, back Jansa."
"I believe Jansa will resist. If not, the next elections will show," Krev said.