The conflict with Islamists has taken a huge toll

The Salafist Group for Preaching and Combat (GSPC) said it backed al-Qaeda's "jihad", or holy war, against the United States.

The GSPC last month claimed responsibility for the kidnapping of more than 30 European tourists in the Sahara desert earlier this year.

Algeria and the US have long suspected that the GSPC was part of al-Qaeda.

The GSPC has been on the US list of "terrorist groups" since 2002.

Algeria has been wracked by a civil war pitting the government against Islamic groups for the past 12 years, in which some 150,000 people have been killed.

Leadership wrangles

"We strongly and fully support Osama bin Laden's jihad against the heretic America as well as we support our brothers in Afghanistan, the Philippines, and Chechnya," GSPC leader Nabil Sahraoui, also known as Abou Ibrahim Mustafa, said in a statement obtained by Reuters news agency.

Profile: Algeria's Salafist group

Some security analysts say this announcement could be linked to recent reports of a change of leadership within the GSPC.

Mr Sahraoui was reported to have replaced Hassan Hattab as leader but other media reports have denied that any change has taken place.

The 32 tourists were kidnapped while travelling in the Sahara desert in February and March.

They were all eventually released, except for one woman who died of heatstroke, after the intervention of neighbouring Mali.