Two men have been detained in France in connection with last year's bombings in Madrid that killed 191 people and injured nearly 2,000, police said.
French agents reportedly acted on a tip-off from Spain
The men - a father and son - were detained in Wervicq-Sud in northern France, close to the Belgian border.
The father was of Moroccan origin and the son has French nationality, AFP news agency said, citing sources close to the case.
Police said the men could be held for up to 96 hours.
They were arrested by heavily armed agents from the Territorial Surveillance Directorate (DST) in early-morning raids, police said.
It was reported that the French police were given the men's details by Spanish investigators.