An Algeria-based Islamic extremist group claimed responsibility Tuesday for a weekend attack that killed a Russian engineer and three others, posting a message on a Web site used by militants.

The message said that Al Qaeda in North Africa claimed responsibility for the Saturday bombing of a bus carrying workers for a Russian company. A Russian and three Algerians were killed, while three others were injured.

The extremist group, which recently changed its name from the Salafist Group for Call and Combat, is the only organized armed group still known to be operating in Algeria's insurgency, which began in 1992. The group claimed responsibility for another attack targeting foreigners in Algeria in December.

The statement said the killing was "a gift to our Muslim brothers in Chechnya who are being killed and oppressed by the criminal Russian government." The Russian government has fought separatists in Chechnya in two wars over the past dozen years. Major fighting died down by 2001, but skirmishes still break out in the largely Muslim region in Russia's south.

Renewed violence has surprised Algeria, steadily emerging from its Islamic insurgency, which has killed more than 150,000 people.

Foreigners were a prime target of Islamic extremists at the height of the insurgency in the 1990s aimed at creating an Islamic state. However, targeting foreigners later grew increasingly rare.

The attack on the Russians occurred near Ain Defla, 145 kilometers (90 miles) west of Algiers. The victims worked for the Russian company Stroitransgaz, which is building a gas pipeline in the area. The Russian government said the bus was being accompanied by Algerian security officers.

An attack targeting a bus carrying foreign employees of an affiliate of U.S. energy giant Halliburton near Algiers in December killed two Algerians and rattled many expatriates. Al Qaeda in North Africa claimed responsibility for that attack.