Cologne, Germany -- Rightists who converged on the German city of Cologne to protest against a planned mosque scuffled with opponents Friday and were prohibited by police from marching into immigrant neighborhoods.

Police have called in reinforcements, fearing riots on Saturday against the "Anti-Islamization Conference."

The far-right rally plans have upset the Islamic world. The government of Iran appealed to Germany to prohibit the demonstration but Berlin says it has no powers to do this.

The German Interior Ministry criticized the rally.

"Such a gathering of populists and extremists harms the co-existence that the city and Muslim citizens have striven for," said an Interior Ministry spokeswoman. She said the integration of Muslims was "a central task."

Chancellor Angela Merkel's spokesman Thomas Steg added that Berlin policies favored "inter-cultural dialogue."

A city group, Pro Cologne, which won 5 percent of votes at the last city council elections, has invited 1,000 to 1,500 rightwing extremists from all over Europe to join it Saturday at a protest against building a grand mosque.

Hundreds of people sympathetic to the mosque plan demonstrated Friday at the empty site, which belongs to Ditib, an organization funded by Ankara to build mosques for Turkish-speaking Muslims.

In low-level violence Friday, reporters saw rightists chase a lone man across a main road and shove him.

Far-left protesters shoved and punched a far-right official and pelted a river cruise boat with stones after the rightists hired it as a venue for a news conference.

Police commanders accused Pro Cologne of endangering public safety by failing to disclose the group's planned movements and prohibited the rightists' planned "tour" on Friday of multi-ethnic neighborhoods as a threat to the peace.

Eight leftists were detained Friday for violence.

Pro Cologne has invited rightists from Belgium, France and Austria to the Saturday demonstration.

The mayor of Cologne, Fritz Schramma, said on Deutschlandfunk public radio, "We don't want their conference and along with a great majority of Cologne people we'll be obstructing them."

Trade unions and mainstream parties forecast 40,000 will attend a counter-demonstration on Saturday.

The mosque, close to a soaring telecommunications tower in a district on the edge of town, is to have a dome 37 meters high and two minarets stretching up 55 meters.

DPA/Expatica