BERLIN (AFP) - A record 17,000 anti-Islamic protesters rallied for their tenth demonstration in as many weeks Monday in eastern Germany, celebrating the rise of their far-right movement by singing Christmas carols.

Germany has for weeks grappled with the emergence of the "Patriotic Europeans Against the Islamisation of the West" or Pegida, whose ranks in the city of Dresden have swelled rapidly from just a few hundred in October.

About 4,000 counter-demonstrators marched through the city under the slogan "Dresden Nazi-free", warning that there was no room for racism and xenophobia in the country that perpetrated the Holocaust.

Most Pegida followers insist they are not Nazis but patriots who worry about the "watering down" of their Christian-rooted culture and traditions. They often accuse mainstream political parties of betraying them, and the media of lying.

Former German chancellor Gerhard Schroeder, of the centre-left Social Democrats, called for concerned citizens to launch a "rebellion of the decent" against the anti-foreigner movement, saying "that's the kind of public reaction we need now".

In the southern city of Munich, more than 12,000 people rallied to voice their opposition to PEGIDA.

In Dresden, the Pegida followers gathered outside the historic Semperoper concert hall for their pre-Christmas recital. Police put their numbers at about 17,500, up from the previous high of 15,000 a week earlier.

The management of the opera house signalled its distaste by turning the building's lights off and flying flags outside that read: "Open your eyes", "Open your hearts", "Open doors" and "Human dignity is sacrosanct", the first line of the national constitution.

The Protestant bishop of Saxony state, Jochen Bohl, said the protesters, by singing Christmas carols, were seeking "to exploit a Christian symbol and a Christian tradition for political action", German news agency DPA reported.

Politicians from all major parties have been stunned by the emergence of the right-wing nationalists who also vent their anger against what they consider a broken immigration and asylum system.

The movement has emerged at a time when Germany, Europe's biggest economy, has become the continent's top destination for asylum seekers, and the world's number two destination for migrants after the United States.

The influx of refugees from Syria, Iraq, Afghanistan and several African and Balkan countries has strained local governments, which have scrambled to house the newcomers in old schools, office blocks and army barracks.

Chancellor Angela Merkel has cautioned Germans against falling prey to any form of xenophobic "rabble-rousing", but several conservative politicians have argued the government must "listen" to the people's concerns about immigration.

Only the small anti-euro AfD party has openly sympathised with Pegida, saying its message has struck a chord.