British police have reportedly detained the country's highest-profile radical Muslim preacher as part of a series of arrests of nine individuals on suspicion of encouraging terrorism and belonging to or supporting a banned organization, according to the BBC and Reuters.

Authorities said the arrests were not connected to any immediate threat to the public. The BBC says officials were searching 18 premises in London and Stoke-on-Trent.

According to the BBC, Anjem Choudary, 47, the former head of the long-banned Islamist group al-Muhajiroun, is the highest profile of the arrests.

Reuters says al-Muhajiroun, banned in 2010, "gained notoriety for staging events to commemorate the Sept. 11, 2001, attacks on the United States with leaflets that referred to the hijackers as 'the Magnificent 19'."

Choudary, in an interview with The Guardian, defended the self-declared Islamic State and called its leader, Abu Bakr al-Baghdadi, "the caliph of all Muslims and the prince of the believers."

In a statement, British police said: "These arrests and searches are part of an ongoing investigation into Islamist-related terrorism." However, authorities declined to confirm that Choudary is among those taken into custody.

Reuters reports that the men arrested, between the ages of 22 and 51, were in custody at police stations in central London.

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