A senior minister of the French government said, on Monday, that there is a “strong possibility” a French national was among the militants of the Islamic State group seen in the video released Sunday showing the execution of American aid worker Abdul-Rahman Kassig, according to media reports.

“There is a strong possibility that a French citizen was directly involved,” French Interior Minister Bernard Cazeneuve reportedly said, citing analysis carried out by French intelligence agencies. "This analysis suggests with a very high probability that a French citizen could have directly participated in carrying out these abject acts."

While Cazeneuve did not disclose the identity of the suspected French militant, several French news outlets said, on Monday, that one of the executioners is Abou Abdallah Al-Faransi, who has reportedly been seen in several other ISIS propaganda videos.

He “is known to have converted to Islam at the age of 17, but he has no prior criminal record in France, like around 50 percent of foreigners who have joined the group,” France 24, a French government-owned news network, said, in a report.

Radio France Internationale, an affiliate of France 24, also reported, citing sources “within the Islamic State group” that a second French national was also a part of the group that carried out the mass executions of at least 18 other men, allegedly soldiers loyal to Syrian President Bashar Assad. The report does not mention the identity of the second French citizen.

The latest reports come hours after French President Francois Hollande joined world leaders in condemning Kassig’s execution.

“These are crimes against humanity…these are barbaric acts and that is why France cannot remain indifferent,” Hollande said, adding that France, which is a part of the U.S.-led coalition carrying out airstrikes against ISIS in Iraq, will continue to fight against the militant group.