A 20-year-old and 18-year-old were arrested by anti-terrorist police in the town of Marignane, near Marseille, in the Bouches-du-Rhone region on Thursday .

The pair were “ready for action” and bought matierials to make explosives”, sources close to the investigation told French daily Libération.

The arrests of two “suspected terrorists” comes one year after self-proclaimed Al-Qaeda inspired gunman Mohammed Merah killed seven people, including three Jewish children in Toulouse and Montauban.

In December last year, Interior Minister Manuel Valls warned that there may be “dozens of other potential Merahs” in France.

“We face an enemy within France, as a result of radicalization,” Valls said in the past.

The two suspects came to police attention when they sent a “threatening email” to US President Barack Obama in November last year.

On their Facebook pages the pair had described themselves as "Jihadists" and had posted around 20 extremist videos on their accounts.

Since then, they had expressed their desire to buy weapons as well as explosives in order “to take action”, police sources told Libération. It was at that point that police took the decision to arrest the men.

“They were potentially very dangerous and we could not afford to take any risks,” the source said.

After the arrest, Interior Minister Valls commended the investigators.

“I pay tribute to the actions of the police and intelligence services, who over the last few months, helped neutralize these particularly dangerous individuals. The threat from terrorism, however, remains high throughout the country.”

France has boosted national security in the light of its operation against Islamic extremists in the north of Mali. Several foreign extremist groups have since made threats to strike France on home soil.