Clashes have broken out in front of Macedonia's parliament between opposition and ruling legislators over next year's budget, as rival supporters pelted each other with stones and bottles.
Six people, including two politicians, briefly needed hospital treatment for injuries from Monday's clashes.
"We are calling for civil disobedience... Macedonia will see a popular uprising," Brank Crvenkovski, leftist opposition party SDSM's leader, told his supporters outside parliament.
"Criticise me, I will explain my decisions, but I ask you not to take the citizens of Macedonia hostage"
- Prime Minister Nikola Gruevski
Crvenkovski said opposition deputies would refuse to take part in future sessions, though such a move would be merely symbolic as the party holds only 29 of the parliament's 123 seats.
Several thousand protesters flocked to parliament after deputies from SDSM party barricaded themselves in an effort to prevent a vote on the budget, which they say will lead to excessive public debt.
SDSM said police detained four of its supporters.
Earlier, security guards had to evacuate speaker Trajko Veljanovski for his safety after opposition deputies tried to physically prevent him from announcing the vote, in a scuffle that left two injured including deputy Radmila Sekerinska.
Another four people including ruling coalition deputy Amdi Bajram were injured in a brawl outside parliament before riot police moved in to separate the protesters, local television reported.
Those injured were briefly hospitalised and their condition was stable, hospital officials said.
Immediately after the opposition deputies left the parliament building, the ruling coalition went ahead with the vote, with 64 of those present approving the draft and four voting against it.
Taking Macedonia 'hostage'
The 2013 budget forecast 2.7 billion euros ($3.5bn) in spending and 2.4bn euros in revenues. The budget is based on a projection of two-percent growth and an inflation rate of 3.5 percent.
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The opposition movement erupted late Sunday when the ruling coalition in the small Balkan country led by Prime Minister Nikola Gruevski approved a revised draft budget.
SDSM deputies decided to physically prevent majority legislators from entering the building.
Gruevski responded by telling the occupants: "Criticise me, I will explain my decisions, but I ask you not to take the citizens of Macedonia hostage" through the action.
Crvenkovski earlier told media that his party was fighting for something much more important than the budget "because if those in power continue down this path they will suspend the constitution... and kill democracy in Macedonia before our eyes."
The opposition has accused the government of unnecessary spending and failing to take serious economic steps.
Macedonia slipped into recession this year, with its economy being strongly hit by neighbouring Greece's financial crisis.
The unemployment rate has reached around 31 percent - one of the highest in Europe - of the working population in this landlocked Balkan country with some two million inhabitants.