BUDAPEST, Hungary — Hungarian special police forces detained 12 people and seized arms and explosives late Tuesday in raids targeting a neo-Nazi group implicated in the killing of a police officer, officials said.

The operation comes three weeks after the killing, in which the officer was shot in the head while searching the home of the head of the Magyar Arcvonal movement.

“Special police forces and anti-terrorist units conducted targeted raids” in about eight locations in Budapest and the northwest of the country, said a police statement.

Twelve people were detained in the raids, “during which explosive materials and various firearms, including pistols and submachine guns, were seized,” it said.

All those detained were linked to branches of the Magyar Arcvonal movement, it said.

Formed in 1989, the paramilitary group is notorious notably for operations to intimidate Jewish and homosexual communities.

Its leader, 76, was arrested immediately after shooting dead the police officer on October 26 in Bony, a village in northwestern Hungary.