In Borno state, in north-eastern Nigeria, there have been two attacks on police stations by groups of armed Muslim militants, and a number of policemen and local residents who opposed the militants have been killed.

Northern Nigeria has a long tradition of Islamic radicalism, but armed confrontations with the authorities are something new.

Northern Nigeria is steeped in Islam, and remains a largely feudal society.

There is still a Sultan, whose authority stretches across national borders and into neighbouring Niger; there are Emirs, drawn from ruling families, with palaces full of courtiers.

This network of wealth and power and privilege has been, and remains, a powerful political force.

Government worried

But alongside it is another tendency, of rejecting this worldly face of Islam, preaching equality, simplicity and a purer way of life.

Charismatic preachers have attracted young men to live a communal life and study the Koran.

But while these groups were often turbulent, and readily came out on the streets in sometimes violent protest, it is only recently that they have led armed attacks on the symbols of government authority, such as police stations.

These groups in the north-east, and another recently in the north-west, have been armed and are prepared to turn their guns on the police.

The young men detained after a previous series of such attacks in Borno - calling themselves the "Taleban" - were also a new type of activist, many of then well educated and from middle class or wealthy families.

Their identification with the Afghan radicals showed they were well informed, and identified with the ideological battles now raging elsewhere in the world - a particularly worrying thought for the Nigerian government.

http://news.bbc.co.uk/2/hi/africa/3679960.stm