COPENHAGEN, Denmark (AP) - A Swedish far-right party that made strong gains in the September election said Tuesday it won't vote for the left-leaning government's budget proposal, likely forcing the collapse of Prime Minister Stefan Lofven's minority government.

COPENHAGEN, Denmark (AP) A Swedish far-right party that made strong gains in the September election said Tuesday it won't vote for the left-leaning government's budget proposal, likely forcing the collapse of Prime Minister Stefan Lofven's minority government.

Sweden Democrats spokesman Mattias Karlsson said his group would attempt to force the government to resign by siding with the center-right opposition in Wednesday's budget vote.

It was not immediately clear if Lofven, a Social Democrat, would resign. He has previously told the daily Dagens Nyheter he could not remain as head of the government if it could not gain a majority in the budget vote.

Lofven could also withdraw the budget proposal for further consideration, which would postpone a vote in Parliament and avert a crisis temporarily.

The Social Democratic leader came to power after the Sept. 14 elections as the head of a coalition with the Greens, promising to reverse many reforms by the previous center-right government.

Karlsson, whose party opposes growing immigration, said Sweden for long has had an "extreme immigration policy."

"That is what worries us Sweden Democrats the most," Karlsson told reporters. He said that social welfare, among other things, had been reduced to pay for the immigration.

In 2012, around 20 percent of Sweden's 10 million inhabitants had foreign roots, including people from western countries, according to official figures. In recent years, immigrants have come mainly from Iraq, Poland and Afghanistan.

The Sweden Democrat's rejection of the budget was seen as a political breakthrough for the anti-immigration group, the country's third-largest party in the 349-seat Parliament.

Despite efforts to soften its image, all other parties have refused to work with the party that has right-wing extremist roots.

The party stands alone in Swedish politics in criticizing the country's liberal immigration laws.