LONDON — A British man accused of terrorist fund-raising launched a High Court bid Monday to halt his extradition to the United States, mirroring a move by radical cleric Abu Hamza al-Masri and others.

Babar Ahmad, 38, has been detained in Britain since 2004 on a US warrant. He is accused of running websites used to raise money for terrorists, and of supplying terrorists with gas masks and night-vision goggles. He has not faced charges in Britain, but has been held without trial the longest of any British citizen detained since the Sept. 11, 2001, attacks.

Last week, a European court decision appeared to have cleared the way for the extradition of Ahmad and four other terror suspects — including Masri — after an eight-year legal battle. Masri, wanted on charges that include helping set up a terrorist training camp in rural Oregon, and Khaled Al-Fawwaz, a second terror suspect, have since filed challenges against extradition at Britain’s High Court.

Britain’s Judicial Office confirmed on Monday that Ahmad had joined them and that a fourth man, Adel Abdul Bary, had filed a separate challenge.