Mohamed Arezki Himeur BBC, Algiers

The new head of the Salafist Group for Preaching and Combat (GSPC) Abou Mossab Abdelwadoud replaces Nabil Sahraoui, who was killed by the army in June.

Mr Abdelwadoud, a famous bomb-maker, has been with the Salafists since 1998.

Several leading Salafists died during June's massive army assault on their base in the Kabylie region - but the movement now appears to be regrouping.

Mr Abdelwadoud, whose real name is Abdelmalek Droukdel, was amongst those initially reported killed in the operation.

The third leader of the Salafist group, Mr Abdelwadoud was one of the signatories to a statement last year announcing the group's alliance with al-Qaeda.

After university in 1995 he joined the Armed Islamist Group (GIA) a precursor to the GSPC which shared its aim of establishing an Islamic state in Algeria.

Mountainous stronghold

Together, the GSPC and the GIA are blamed for some 150,000 death since in an insurgency that began in 1992 following the military's cancellation of elections to keep an Islamic party from power.

The GSPC is now the biggest and best organised of Algeria's Islamist groups.

It operates mainly in the Boumerdes and Kabylie regions of the country, with many of its fighters based in inhospitable mountainous terrain.

This makes it almost impossible for the Algerian army to wipe out the organisation, despite big military operations such as that conducted three months ago.

The Salafists have stepped up attacks in recent days, especially in the Boumerdes region, east of the capital, where they have killed a number of soldiers and policemen.