BERLIN: Berlin authorities said they arrested six people Sunday over an alleged plot to carry out a "violent crime" at the German capital's half marathon which attracted 36,000 runners and big crowds of onlookers.

Prosecutors and police said in a statement they had received "isolated indications that those arrested (Sunday) between the ages of 18 and 21 may have been involved in planning a violent crime in connection with this event".

The security authorities said that on that basis and after a deadly van rampage on Saturday in the western German city of Muenster, they decided to swoop on the suspects.

"Due to the still ongoing investigation, no further information can be provided at this time," they added.

The statement spoke only of "several" arrests but a tweet by the police mentioned six arrests carried out by special forces.

Berlin Mayor Michael Mueller thanked security forces for preventing an "impending attack with their vigilance and police work".

A police spokesman told AFP later that they had confiscated "data storage devices, mobile phones, two vehicles and a small knife" during the raids.

He confirmed that the suspects arrested "might have planned something during the half marathon" but "we don't know what exactly".

The half marathon went off early Sunday without incident amid warm spring sunshine.

Berlin's top security official, Andreas Geisel, had said that the city of 3.5 million people would need to review its precautions for the half marathon following the Muenster attack in which two people were killed.

Some 630 police officers were deployed to guard the race.

Authorities believe the 48-year-old German perpetrator of the Muenster attack, who shot himself dead, had mental health problems and was not politically motivated.

A report by daily newspaper Die Welt which police did not confirm said that the main suspect in the Berlin probe planned to attack race participants and onlookers with two "specially sharpened knives".

It added that the suspect had links to Tunisian asylum-seeker Anis Amri, who carried out a deadly truck attack on a Christmas market in the German capital in December 2016.

In Germany's worst jihadist attack to date, Amri hijacked a truck and murdered its Polish driver before killing another 11 people and wounding dozens more by ploughing the heavy vehicle through the crowd.

He was shot dead by Italian police in Milan four days later while on the run.

A source close to the investigation told AFP that the Welt reports that a knife attack was being planned "went too far".

The daily Tagesspiegel reported earlier that a "foreign intelligence service" had warned Berlin police of the possibility of an attack on the half marathon. And it confirmed the suspicion of a link between one of the suspects and Amri.

Police declined to comment on the report.

Like other European nations, Germany remains a target for Islamist militant groups, in particular, because of its involvement in the coalition fighting IS in Iraq and Syria, and its deployment in Afghanistan since 2001.

A court last month sentenced a 26-year-old Palestinian asylum seeker to life in prison for killing one and wounding six others with a knife in a Hamburg supermarket out of a "jihadist" motive last July.

Germany's security services estimate there are around 10,000 Islamist radicals in Germany, some 1,600 of whom are suspected of being potentially violent.

Political opponents of Chancellor Angela Merkel, including the far-right AfD party, have charged that the security situation has worsened with the arrival of more than one million migrants and refugees since 2015, many from African and Middle Eastern conflict hotspots. — AFP </s> Police cars are lined up in front of an apartment building in Chemnitz, Germany, on Saturday, Oct. 8, 2016.

BERLIN — German police are searching for a man suspected to have been planning a bombing attack after a raid on his apartment in the eastern city of Chemnitz turned up nothing, authorities said Saturday.

Police raided the apartment after receiving information from Germany's domestic intelligence agency on Friday night about the alleged attack plans, Saxony police spokesman Tom Bernhardt told reporters.

Neighbors reported hearing an explosion, but that was the police assault team blowing open the apartment's door, police spokeswoman Kathlen Zink told The Associated Press.

She said police found nobody in the apartment, that that they are now searching for the suspect.

She refused to provide details about the suspect or about whether any explosives had been found in the apartment.

"The investigation is continuing," she said.

Germany has been on edge since two attacks this summer claimed by the Islamic State in which multiple people were injured and both assailants died. Two other attacks unrelated to Islamic extremism, including a deadly mall shooting in Munich, have also contributed to fears. </s> Two alleged supporters of a neo-Nazi terrorist group have been arrested after 155kg of explosives were discovered in Germany.

One suspect had built a homemade bomb emblazoned with a swastika and symbol of the Nazi SS, prosecutors announced on Saturday.

The men, aged 18 and 24, were arrested after the explosives were discovered inside a house in Lauterecken, causing more than 80 local residents to be evacuated from the surrounding area so the material could be safely removed.

The pair denied planning a terror attack when they were arrested in December, SWR television reported, claiming to be amateur pyrotechnics preparing for a New Year’s Eve firework display.

The two men, of German origin, are being held on suspicion of violating explosives laws and preparing a “serious act of state-threatening violence”.

Prosecutors are examining a possible link to the Oldschool Society (OSS), an extremist organisation known to have planned attacks on refugee centres and mosques since it emerged in 2014.

A spokesperson said the teenage suspect told investigators he had attended an OSS meeting in Rhineland-Palatinate state over the summer, the DPA news agency reported.

Four members of the group are already on trial in Munich for allegedly planning an attack on asylum seekers.

Federal prosecutors charged the three men and a woman with “establishing a terror organisation” and preparing attacks using explosives in January 2015.

Officials said members had planned to bomb refugee accommodation in the German town of Borna, and travelled to the Czech Republic to buy pyrotechnics which they planned to make into bombs packed with nails and fuel.

The interior ministry has classified the OSS as a dangerous organisation but it was also dubbed the “stupidest terror group in Germany” by media reporting that members discussed plots openly on Facebook.

A rise in extremism has been documented in Germany since the start of the refugee crisis and a series of terror attacks, with far-right groups including Pegida staging protests against immigration and the “Islamification of Europe”.

Numerous attacks on refugee centres have been documented as part of a rise in political violence by both the right and left wing.

German security services also remain on alert for possible Isis-inspired terror attacks following the massacre at a Berlin Christmas market and two previous attacks over the summer.
German media uncover a large ISIL terrorism plot which had been foiled in 2016.