Police in Copenhagen have said one Irishman was among the hundreds of people arrested as part of the recent violence in the city following the eviction of activists from a Copenhagen youth centre earlier this week.
They said the man was arrested on Friday and has since been released and deported.
Danish police said they raided houses, schools and hostels, detaining about 100 activists, including Germans, Swedes, Norwegians, Italians, British and Spaniards. Local media put the figure at 600.
The arrests followed some of the worst violence early on Saturday, when police fought street battles with hundreds of youths who torched cars and vandalised a local school.
Media reports said organisers sought to rally supporters for fresh demonstrations via mass cellphone text messages. Police were braced for fresh clashes on Saturday night and drafted reinforcements from other districts and borrowed police vans from Sweden, police spokesman Flemming Steen Munch said.
Attempts to restart violence last night were quickly quashed by police. A demonstration in Copenhagen's multi-ethnic, working class Norrebro district was dispersed by police when some youths began hurling Molotov cocktails.
Earlier in the day, a peaceful demonstration was held ending in Norrebro district, the focus of recent protests with the hippie enclave Christiania.
"It's a lot calmer tonight," a police officer said.
The conflict over the youth centre has simmered since 2000 when local government, which had lent it to the youngsters since 1982, sold the building to a religious group. Police moved to evict the squatters early on Thursday, implementing a court order issued last year.
Activists have vowed to keep up the protests to retake control of the worn-down building in Norrebro in which artists such as Nick Cave and Bjork have performed.
The youths have repeatedly called for a political solution to the dispute over the youth centre but rejected a proposal to move to another building.