Police in Montenegro have fired tear gas at opposition supporters who hurled fire bombs and torches to demand the resignation of prime minister Milo Djukanovic's government, which hopes to steer the Balkan country towards Nato membership later this year.
Several thousand protesters charged at the parliament building in the capital Podgorica, shouting "Milo Thief" and throwing objects including fire-bombs at riot police guarding the site. Police responded with tear gas and officers in armoured vehicles chased away the demonstrators.
Witnesses said several shop windows were broken in the unrest, as tear gas smoke enveloped the city centre.
Fifteen policemen were hurt, while 24 protesters sought medical help because of tear gas. One opposition leader was detained.
Anti-government protesters gathered earlier at a central square, pledging to bring down the government. Opposition leader Nebojsa Medojevic shouted "the dictator must fall", referring to Mr Djukanovic, who has been in power for 25 years and whom opposition accuse of authoritarian rule.
Some of the demonstrators carried banners reading "No to Nato" and "For military neutrality of Montenegro". Zoran Kovacevic, 57, an unemployed electrician, said: "We are against Nato, but most of all we are hungry."
Police used tear gas twice last week against stone-throwing government opponents, who are also calling for early elections and a referendum on whether Montenegro should join Nato.
Montenegro's pro-Western government hopes to be invited to join the military alliance in December, but many Montenegrins with historic ties to Russia remain opposed.
The Adriatic nation of some 600,000 people split from a union with much larger Serbia in 2006.