BERLIN — German authorities banned three ultraconservative Islamic groups Wednesday and separately announced they had foiled a suspected assassination attempt by Islamist extremists against a prominent far-right politician.
The groups banned included one whose Internet propaganda videos helped inspire the extremist who killed two American airmen at Frankfurt airport in 2011, the country’s domestic intelligence chief said.
Police launched early morning raids on 21 apartments and one meeting room belonging to DawaFFM, Islamic Audios, and al-Nussrah — all of which adhere to the hardcore conservative Salafi interpretation of Islam.
The groups were largely involved in recruitment, fund-raising, and propaganda, including videos and other postings urging people to fight against those who did not believe in their version of Islam, said Hans-Georg Maassen, the head of Germany’s domestic intelligence service, the Office for the Protection of the Constitution.
‘‘These organizations are oriented against the basic right to freedom of religion — against Christians and other faiths including Shi’ites,’’ Maassen said.
For example, he said, in one DawaFFM YouTube posting, an Arabic speaker told Shi’ite Muslims: ‘‘If the Prophet Muhammad heard your words he’d hack off your hands and feet and banish you from the earth.’’
It was DawaFFM YouTube videos and Facebook postings that helped radicalize Arid Uka — the lone-wolf attacker who killed two US airmen and injured two others at the Frankfurt Airport in 2011, Maassen said.
Uka was convicted of murder last year and sentenced to life in prison.
In an operation unrelated to the ban on the groups, police arrested four men overnight on suspicion of planning to murder the leader of a far-right fringe party known as pro-NRW.
Two of them were arrested in a vehicle near the home of Markus Beisicht in the western city of Leverkusen, police said in a statement. Two other men were arrested when police searched private properties in Essen and Bonn, where a firearm and ‘‘material suitable for the manufacture of explosives’’ were also found.