Prosecutors were seeking arrest warrants against a further 10 suspects.

During police raids in the Bavarian town of Bamberg, police seized a gun, knives and illegal fireworks, well as far-Right propaganda material including a red flag bearing a swastika.

German police have foiled a far-right plot to attack refugee shelters in Bavaria amid growing violence against migrants, authorities said Thursday.

Detectives observed the group of 11 men and two women for more than a year before swooping in on Wednesday morning, seizing illegal firecrackers, a firearm, ammunition and other weapons.

In the past week, investigators intercepted 35lb of fireworks the group had ordered from eastern Europe, including so-called “ball bombs” from Poland.

The police was talking about the “highly risky explosives” that far-right extremists planned to use in an attack on two government shelters for asylum-seekers in the town.

“It is a violent group that is characterized by extreme right-wing ideology and the fight against leftist groups and refugees”, state prosecutor in Bamberg, Erik Ohlenschlager, told local reporters.

“Alongside the attacks on asylum-seeker hostels, attacks against officials held responsible (for the influx of migrants), such as politicians or the managers of lodging places, could grow”, a BKA spokesperson told Agence France Presse (AFP).

Werner Mikulasch, the deputy police chief for Upper Franconia, said explosives experts determined that the “ball bombs” could have blown out windows if thrown near the asylum-seekers’ homes, or caused serious injury or death in a confined space.

It was suspected they were planning to carry out an attack on October 31 to coincide with a planned demonstration in the town.

During July, August and September, there were 285 attacks on migrant centres across Germany – more the entire number in 2014, which stood at 198 offences, the BKA said.

Police in the historic city of Bamberg suspected a centre for refugees arriving in Germany through the Balkans to be the gang’s target.

Henriette Reker, the new mayor of Cologne, was stabbed and seriously injured by a far-Right extremist over her support for refugees just hours before she was elected last weekend.

There have been a total of 505 attacks on refugee shelters so far this year, including arson, vandalism and graffiti, according to newly released figures.