Four protesters were arrested on Saturday afternoon in front of the parliamentary building when they started scuffling with police.

"We have arrested four people who were trying to cause trouble," Finn Belle, an Oslo police officer, told reporters.

The four were among some 25 supporters of Anti-NDL and New SOS, which called and organized a counter-protest at the same spot when about 30 SIAN (Stop Islamization of Norway) supporters were demonstrating to voice their opposition against what they called abusing democracy.

The Anti-NDL and New SOS, which say they are anti-racist organizations, shouted slogans "No to SIAN, Yes to diversity" at the opposite side.

SIAN leader Arne Tumyr was quoted as saying that "we can not have special rules for Muslims."

SIAN called Saturday's demonstration as a response to the recent protests in many Muslim countries against the anti-Islam American film -- "Innocence of Muslims."