Up to 50 people were arrested, mostly in the Paris area, but addresses in provincial cities including Lyons and Marseilles were also raided.

BBC correspondent Stephen Jessel: "No coincidence in timing" (35")

Police are playing down a connection with the World Cup that kicks off on June 10 but BBC correspondent Stephen Jessel in Paris says the timing cannot be a coincidence.

Morocco and Tunisia are among the 32 qualifying nations and the correspondent says a successful attack by a militant Algerian Islamic group would be an immense propaganda coup.

Tunisia play their first game in Marseilles against England on June 15.

A suspect is taken into a Paris police station

The searches were carried out on the orders of four French judges with responsibility for combating terrorism.

Similar operations were arranged in Germany, Belgium and Italy, where nine people were arrested.

The raids were directed at people suspected of providing material or support to radical Algerian organisations such as the Armed Islamic Group of GIA, which is fighting to overthrow the Algerian Government.

France suffered a series of bomb attacks in 1995, blamed on Islamic radicals, which killed eight people and injured more than 170.

In 1996, an explosive device killed four people in a Paris station of a commuter rail line.

Police officials have previously expressed concern that Islamic fundamentalists could be tempted to take advantage of the worldwide television and media coverage that the World Cup brings to stage attacks in France.