BAMAKO, Jan 18 (Reuters) - Mali's army has arrested a hardline Islamist judge who ordered floggings, amputations and the stoning of women for adultery during a 10-month occupation by rebels linked to al Qaeda.

Houka Houka Ag Alfousseyni, who held court in the Timbuktu region, was detained on Friday as part of a military operation against armed Islamist groups that are plaguing local communities, the government said in a statement.

Alfousseyni was one of the rebel movement's most influential and well-known figures, and his arrest is part of a government campaign to bring to justice radical Islamist leaders like him.

Al-Qaeda-linked fighters hijacked a rebellion by Tuareg separatists in Mali's desert north after a 2012 army coup, occupying large swathes of the country and imposing Sharia law.

France, saying the Islamist rebellion posed a threat to Western security, launched a massive military intervention in its former colony in January last year, scattering the fighters across Mali and into neighbouring countries.

But Islamist groups have regrouped in recent months, stepping up their operations.

In December, the authorities arrested the former head of the Islamist police in the northern town of Gao who also imposed Sharia law. Both arrested men held their posts only under the rebels. (Reporting by Tiemoko Diallo and Adama Diarra; Editing by Matthew Mpoke Bigg and Raissa Kasolowsky)

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