Three people aged between 19 and 24 are being held and questioned on suspicion of preparing a terrorist act, French prosecutors said today, confirming media reports.

According to French TV station RTL, the main suspect is aged 19, lives in Dunkirk, in northern France, and after police searches, explosive materials were found in his home.

According to Le Parisien newspaper, he had declared, via the internet, to be friendly with the Islamic State and was preparing terrorist acts against a variety of targets.

French media report that two other people close to him have been arrested since his arrest, but their lawyers say they have no connection to the Islamic State and the carrying out of terrorist acts.