A Spanish court Friday remanded a suspected Al-Qaeda extremist in custody on suspicion of terrorist offences for running jihadist Internet forums.

Among the online activities of the suspect, Mudhar Hussein Almalki, police say he praised the French Islamist Mohamed Merah who shot dead seven people in southwest France, according to a written court ruling.

Spain's top criminal court ordered Almalki, identified by police as a Saudi national, to be held in provisional detention without bail "for the suspected crime of belonging to a terrorist organisation", it said.

Police suspect him of belonging to the "Ansar Al-Mujahedeen network" running online forums aimed at "recruitment, indoctrination and radicalisation of sympathisers for armed jihad".

The court added that Almalki posted a message praising Merah on March 22, after the Frenchman of Algerian descent was killed in a police siege in Toulouse.

When Almalki was arrested in Valencia on Tuesday, Spanish Interior Minister Jorge Fernandez Diaz said there was no connection between his case and that of Merah.

The minister said Almalki "was known within the organisation as Al-Qaeda's librarian" -- an apparent reference to his online document-sharing activities detailed in Friday's ruling.

The court said Almalki shared material online about poisonous gases and explosives and took part in publishing a list of recommended targets for attacks, including former US leader George W. Bush and Britain's Tony Blair.

Almalki has three days to appeal the detention order.