By Ren Ke, Zhang Yuan, Xu Yang

BERLIN, May 27 (Xinhua) -- A total of tens of thousands of demonstrators on Sunday joined in Berlin in two separate groups -- one for the populist right-wing party Alternative fuer Deutschland (AfD) and another against it, lashing each other on issues of refugees and racism.

The AfD said between 2,500 and 5,000 party supporters are at the pro-AfD rally, which was outnumbered by the protest against it, as the Deutsche Presse Agentur (DPA) quoted the police as saying that over 25,000 demonstrators gathered against the party.

Security has been beefed up throughout the city to avoid clashes between AfD supporters and their opponents. However, many of the protests against the AfD appeared to have peaceful and even fun themes, including a rally on boats on the River Spree.

In front of the Bundestag anti-AfD protestors rallied on the grassland, with activists calling for boycotting the party and distributing brochures and papers with slogans.

"Stoppt den Hass" (Stop the Hate), an umbrella of anti-AfD protest groups wrote. "Racism is no alternative," many people held papers with this slogan. Germany's major political groups, including the Die Linke, the Social Democratic Party (SPD), the Greens and others also showed their solidarity against the right-wing populism.

On a stage in front of the Bundestag some Muslim women with loudspeakers denounced the AfD, which is against Islam in Germany. Boys and girls joined the rally with their parents and techno on boats were playing music to show their support for diversified culture.

"I want AFD out because it is a rightist party who only wants Germans to live in Berlin. You know Berlin has always been a city with different nations living together. It's simply not right to have only one people living here," Antje Kanitz told Xinhua among the anti-AfD demonstrators.

While on the other side, AfD members and its supporters walked from the landmark Brandenburg Tor to Berlin Central Railway Station, waving mostly German national flags, and anti-Euro flag and anti-Islam banners. Another banner read, "A. Merkel.... She is a rights breaker."

"Too many new people are coming into Germany and you can see that we are like having a civil war due to Merkel. It's a consequence of her policy," said a man to Xinhua in his 50's named Schmidt among the AfD rally, which was heavily guarded by the police.

He referred to Merkel's opening-door policy towards over one million refugees, mostly Muslims from war-torn Middle East who came to Germany since the summer of 2015.

Founded in 2014, the anti-immigration, anti-Euro AfD gained popularity among the refugee crisis and in the federal elections in September 2017, the party crossed the 5-percent threshold, becoming the first right-wing populist party after WWII in Bundestag, the German Parliament.

The rise of the far-right politics coincided with a spike in anti-Semitism and surging attacks targeting refugee accommodations throughout Germany.

Annegret Kramp-Karrenbauer, Secretary-General of the ruling Christian Democratic Union party (CDU), accused the AfD of anti-Semitism. She said in an article of the weekly Bild am Sonntag that the party was a threat against Jewish life in Germany and had brought anti-Semitism into German parliament.

However, AfD co-chairman Joerg Meuthen fought back against Kramp-Karrenbauer's views, saying the CDU instead was a threat to "Jewish life in Germany with its migration policy allowing masses of people from the Islamic world to immigrate without any conditions."

Latest polls showed that the AfD has around 14 percent of supporting rates, just 3 percentage points after the second largest party, the SPD.

But the demonstrations on Sunday displayed that the AfD arose public anger, as their momentum was obviously pressed down by other political groups on the other side of River Spree, or ordinary people who just passed by.

The two groups were separated from each other by the police. Despite exchanging insults at some crossroads distantly, the demonstrations on Sunday were quite peaceful.

The police deployed 2,000 armed-to-the-teeth officers to guard the demonstrations, blocking the most central area of Berlin.