Few countries have suffered as much from terrorism as Algeria. For more than a decade after the aborted elections in 1992 Islamist extremists waged a bloodthirsty war against the state, targeting women, children, market places and even whole villages. Families were rounded up and had their throats slit. People were burnt alive in their homes. The Islamic Salvation Front and Armed Islamic Groups (GIA) used extreme brutality to drive out foreigners, intimidate the population and virtually close down normal life in the cities. In all, about 200,000 people were killed, as the shadowy military authorities answered the attacks with bloody reprisals and a crackdown on civil liberties.

Only in the past three or four years has Algeria begun to emerge from the violence that engulfed what was once one of Africa’s most industrialised and developed economies. The bombs that killed 30 people in the capital yesterday have raised, therefore, immediate fears across the region that the terrorists, now openly affiliated with al-Qaeda, are preparing to mount a deadly campaign across North Africa. The virus of Islamist extremism is far from defeated.

There have been plenty of warning signs in recent months. In January the main terrorist organisation, the Salafist Group for Preaching and Combat, changed its name and deepened its ties to al-Qaeda. Since then it has claimed responsibility for a new wave of attacks targeting the security forces and foreigners. Meanwhile, the Army has stepped up operations against insurgents in the mountains east of Algiers. Five days ago nine soldiers and at least six Islamist militants were killed when a military convoy was ambushed west of the capital. Nor is Algeria alone in struggling to contain terrorism. Tunisia faces a similar challenge from Islamist groups, and in Morocco yesterday police were hunting ten possible suicide bombers in Casablanca, a day after three suspected militants blew themselves up as the police closed in. All were wanted in connection with the bombing of an internet café last month.

The Maghreb is fertile ground for extremists posing as devout Muslims. Burgeoning populations, high unemployment, inefficient but repressive governments and a lack of press and civic freedoms have all fuelled popular frustration. The region is rich in oil and gas resources, has a fertile littoral and enormous tourist potential. But poverty is widespread, education levels are low and economic development has been stultified by bureaucracy and corruption. Opposition has been driven underground and, as in 1992 when the Algerian military staged a putsch to prevent Islamic groups assuming power, religious extremists have gained influence.

North Africa is an obvious haven for al-Qaeda, under pressure in the Middle East, where governments have targeted its leadership. The Maghreb is also close to Western Europe. Extremists have been able to set up cells among the large numbers who have migrated, often illegally, to Spain, France and Italy. France, with strong historical ties to its former colony, has been shocked by the renewed violence: the threat to its own security was underlined this week by the announcement than an Algerian will stand trial later this year for alleged complicity in the 1995 Paris métro bombings. As Britain has found, to its cost, Algerian terrorists have been active across Western Europe. We are vulnerable to their attacks and must be both vigilant and very supportive of the people of North Africa.