Juncker told German papers belonging to the media group "Funke Mediengruppe" on Saturday that if hate slogans heard at demonstrations and similar incitement can result in attacks on people, then he was prepared to worry about these "so-called citizens."

The EU Commission's president said, however, that the vast majority in Germans have shown "heart instead of hate" - a slogan which has been widely used at anti-xenophobia demonstrations.

"That gives me courage," Juncker said.

Increase in attacks

Juncker's worries follow a series of xenophobic attacks across Germany. The number of attacks against refugee shelters, for example, has more than doubled this year compared to 2014.

Just last weekend, the new mayor of Cologne, Henriette Reker - who is known for her pro-refugee stance and organization of migrant accommodation in the city - was the victim of a xenophobia-motivated knife attack.

The Central Council of Jews in Germany on Saturday called on the government to take decisive action against right-wing extremism.

"The fight against growing right-wing extremism must be a top priority both for politicians and security authorities," the council's president Josef Schuster told "Mitteldeutsche Zeitung," a German newspaper.

"Germany must be able to protect both asylum seekers and volunteers. The recent warnings from the Federal Criminal Police (BKA) of increasing right-wing violence should be taken seriously," Schuster said, adding that the German police force needed more staff.

New asylum rules in force

The comments on Saturday came as Germany's much-debated asylum seekers policy came into action.

The main aims of the amended asylum package are to speed up asylum procedures and ensure that rejected asylum applicants quickly return to their home country. As part of the reforms, refugees allowed to stay in Germany should also be provided with better means to integrate into society.

The changes to Germany's asylum policy have been met with some harsh criticism, however, even from within Chancellor Angela Merkel's own Christian Democratic Union (CDU), from party members who have described the policy as "unsustainable."

The prime ministers of Serbia, Bulgaria and Romania were due to hold talks on Saturday about how to deal with the influx of refugees over the winter months. In a separate mini-summit on Sunday, a handful of EU member states and non-EU members are scheduled to discuss a coordinated response to the crisis.

ksb/rc (Reuters, AFP, AP, dpa, epd)