Five leaders of Germany's anti-Islamist organisation Pegida have resigned amid increasing criticism about the group's "racist" agenda.

Face of the group Kathrin Oertel had received "massive hostility, threats and career disadvantages" as a result of her involvement, a statement from the group released yesterday said.

"She has sacrificed herself for the cause, but even the strongest of women has to take time out when at night photographers and other strange figures are sneaking around outside her house."

Four other members of the executive board have also resigned. Local reports say this is due to the controversy about founder Lutz Bachmann's racist attitudes.

Bachmann was forced to resign last week after reportedly branding asylum-seekers "animals" and "scumbags" and a photo of him posing as Hitler went viral.

However, German press claims that Bachmann remains influential within Pegida. One of those who quit told Frankfurter Allgemeine Zeitung magazine that the former leader was the true force behind the resignations.

Supporters of Pegida (Patriotic Europeans Against the Islamisation of the West) are calling for Germany to be protected from what they see as the "Islamisation" of the country by Muslim immigrants.

Weekly protests have attracted up to 25,000 people, though counter-demonstrations have garnered even greater support. The movement has been accused of fostering racism and inciting hatred, but it has managed to spread throughout Germany.

German Chancellor Angela Merkel has strongly condemned the group, saying in an address at the start of the year that those who led the rallies "have prejudice, coldness, even hatred in their hearts".

Cologne Cathedral turned out its lights in protest against Pegida's marches earlier this month.

"PEGIDA is made up of an astonishingly broad mix of people, ranging from those in the middle of society to racists and the extreme right-wing," cathedral dean Norbert Feldhoff told Reuters.

"By switching off the floodlighting we want to make those on the march stop and think. It is a challenge: consider who you are marching alongside."

Monday's rally in Dresden has been cancelled, but Pegida has pledged to resume its protests the following week.