The Serbian capital Belgrade has seen its biggest anti-government protest in years as thousands of disenchanted Serbs demanded early elections.
At least 55,000 people turned out in front of parliament after the opposition Serbian Progressive Party called the rally.
Party leader Tomislav Nikolic gave the government two months to call polls or face a civil disobedience campaign.
Serbia's economic woes have continued as it moves towards EU membership.
A disparate 10-party coalition, united around EU integration, has been in power since 2008, led by Prime Minister Mirko Cvetkovic and President Boris Tadic.
The next general election is not scheduled until 2012.
'Unfulfilled promises'Police put attendance at the rally at 55,000 people while an AFP news agency correspondent reported 70,000.
As riot police stood by, protesters, some of whom had arrived by bus from cities across Serbia, gathered in front of parliament holding banners reading "Democratic Party, time to go" and "We are hungry".
Police closed off parts of the city centre to accommodate the demonstration, which is said to have passed off peacefully on an unusually mild, sunny day.
Clearly referring to events in Egypt and Tunisia, Mr Nikolic told the protesters: "Elsewhere in the world people are telling governments they should listen to the people.
"I know you are disenchanted and bitter over this dishonest government which is tormenting you. Let us torment government instead".
Mr Nikolic's party is seen as the strongest opposition challenger to the Serbian Democratic Party, which leads the coalition.
"I was not a Nikolic voter in the past but now I am so disillusioned because of unfulfilled promises, poverty, corruption and hardship," metal worker Dragomir Djuric, 56, told Reuters news agency. BBC News
