PARIS: French counter-terrorism police arrested a 15-year old boy on Wednesday following two recent thwarted attacks, marking the third such arrest of a 15-year-old in a week.

A security official said the suspect was arrested in northeastern Paris and turned 15 only a few days ago.

In a separate case, a 15-year-old was arrested last Thursday on suspicion he was about to carry out a knife attack, a judicial official said on Wednesday.

Yet another 15-year-old was arrested Saturday on suspicion of planning something similar.

The two officials were not authorized to speak publicly about the cases and demanded to remain anonymous.

It was unclear if the three boys knew each other, in real life or online.

However, officials are investigating if a potential link could be Rachid Kassim, who they say is a French Islamic State member tied to at least four plots to attack France since June.

The boy arrested on Wednesday has links to Kassim, according to the security official, while the judicial official said investigators were trying to verify whether the boys arrested Saturday and Thursday also had links to the terrorist.

The boy arrested on Thursday in Rueil-Malmaison, west of Paris, was handed a preliminary charge three days later of criminal terrorist association, the judicial official said.

Investigators were also trying to verify whether he had links to Adel Kermiche, one of two young men who slit the throat of a priest as he said Mass in a church in Normandy in June.

Kassim's precise role is under investigation, but he is believed to have become a key instigator who directs recruits in encrypted forums on how and where to carry out the Islamic State (IS) group's call for European Muslims to strike at home.

Most recently, he was believed to be in contact with a 19-year-old in an unprecedented cell of French women who failed in their attempts to detonate a car bomb near Notre Dame Cathedral and kill police.

Interior Minister Bernard Cazeneuve said that Wednesday's arrest was part of French authorities' efforts to target people vulnerable to “calls to carry out killings, led by a certain number of actors in Syria.”

But he didn't elaborate on any direct links between the boy and the IS group.

The militant group “uses encrypted means to encourage increasingly young” individuals, he said, citing the messaging application Telegram.

France is currently in “an exceptional level of mobilization” following two failed attacks in six days, he added.

France has been in a state of emergency since the Paris attacks last November that killed 130 people.

Despite more than 10,000 security forces in the streets, there have been three attacks this year, including a Bastille Day truck attack in Nice that killed 86.

Young teenage suspects are confounding even communities where they live.

Frederique Calandra, the mayor of the Paris district where the boy in Wednesday's arrest has lived with his family, said on BFM TV that he attended school and “is not known” to a local prevention unit for fragile youths that regularly brings together representatives of police, justice and the education system.