Sunday's bombing in Tizi Ouzou underlines Algeria's inability to effectively stamp out terrorism. Algerian security services have improved their counter-terrorism tactics since the 1990s but formation of the group Al Qaeda in the Maghreb in 2006 has reinvigorated terrorism across the country despite increased police raids and the stricter control of chemicals used in bomb making.

Just ten days ago, Algerian authorities promised to completely secure the city of Tizi Ouzou by 2009. But after Sunday's suicide bombing these promises sound hollow. The attack targeted a police station in the city and 25 people were wounded in the blast. 

Algeria has improved its counter-terrorism strategy since the 1990s but the security services are now dealing with a reinvigorated enemy. In 2006 the Algerian terrorist group GSPC pledged allegiance to Al Qaeda, to become Al Qaeda in the Maghreb.

Since then, terrorism has risen to new heights. Suicide attacks and car bombs are now the weapons of choice. Algerian authorities have been struggling to find the masterminds and have stepped up police raids.

A break came in 2007 with the arrest of Fatah Bouderbala, bomb-maker for Al Qaeda in the Maghreb. A rocket launcher and more than 800 kilos of explosives were found in the raid, leading police to ban the sale and use of certain fertilizers like ammonium nitrate.

A key ingredient for explosives

Another chemical targeted by Algerian investigators is the anaesthetic gas nitrous oxide. Authorities have restricted its use, leading to shortages in many Algerian hospitals.

Security services have foiled several planned attacks this year but they've been unable to eradicate the Al Qaeda threat.

Authorities have nevertheless succeeded in preventing any further attacks in the capital Algiers since the bombing of the UN building there in December 2007.