Police in northern France have held two men for questioning in relation to the Madrid bombings of March last year in which 191 people died.
Heavily armed and hooded security forces raided a house at Wervicq-sud, near Lille, close to the Belgian border, and detained a Moroccan national and his son who has French nationality.
They were acting on information provided by Spanish investigators.
The Madrid bombings were Spain’s worst ever terrorist attack in which nearly 2,000 people, most of them commuters, were injured.
Spanish police have rounded up more than 100 Islamic radicals, many of them of North African origin, in connection with the bombings.