German police cancelled an anti-Islamic congress planned for today in Cologne after leftist opponents of the rally clashed with its right-wing backers.
The group Pro-Cologne called the rally to oppose a decision by local authorities in Cologne, Germany's fourth largest city, to allow the construction of a mosque with a high dome and minarets.
It invited like-minded nationalist groups from around Europe to join the "Stop Islam" rally to fight what it called the "Islamisation and immigration invasion" of Germany and Europe.
"The rally has been cancelled," a police spokesman said. Many protesters cheered the announcement. A spokesman for Pro-Cologne said they were surprised by the cancellation.
Police said 40,000 people protested against the rally. It had been expected to attract 1,500 people but only dozens made it.
Most of the protesters were peaceful, although roads and rail lines leading to the centre of Cologne were blocked by demonstrators in sit-down strikes.
But gathering of Pro-Cologne participants on a Rhine River pleasure boat yesterday evening turned violent when stones hurled by leftist protesters from the shore broke windows. There were further clashes between small numbers on both sides today.
Three thousand police were on duty to keep the two sides apart. One police officer was injured.
Left-wing demonstrators blocked a rail line which a group of 150 right-wing activists were using to travel into the city centre from the airport, police said.
Some of the protesters carried placards reading "Nazis out of Cologne" and "Temples, synagogues, churches and mosques - everything's okay".
"We're here to show racism the red card," said Cologne mayor Fritz Schramma. "Racists and extremists aren't welcome."