The security forces destroyed a school, a clinic and the living quarters of the sect in the north-western Sokoto state.

Although no official explanation was given for the demolition, it is being suggested that it is part of a plan to expel the group from the city.

Shia leader Kasimu Rimin Tawaye and some 100 followers remain in detention.

Mr Tawaye and his supporters were arrested after street fighting between them and followers of a prominent Sunni cleric, who was shot dead three weeks ago.

The cleric, Umaru Danmaishiyya, well-known in Sokoto for his sermons against Shias, was shot in a mosque on 18 July and died the following day.

A man was lynched shortly after the shooting and Sunni mobs tried to attack a Shia residential compound.

Sokoto, a deeply religious city, sits on the fringes of the Sahara desert and is the seat of the Sultan of Sokoto, spiritual leader of Nigeria's estimated 70 million Muslims.

In the past Sokoto has avoided the unrest that has affected many other northern Nigerian cities.

The Sokoto state government is expected to issue a statement shortly on the decision to demolish the Shia headquarters.