"The person who carried out the operation in Nice, France, to run down people was one of the soldiers of Islamic State," the Amaq news agency affiliated with the militant Islamist group said on its Telegram account, Reuters reported.
"He carried out the operation in response to calls to target nationals of states that are part of the coalition fighting Islamic State," the report said.
French authorities have yet to produce any evidence that the 31 year-old Tunisian killer, shot dead by police in the attack, had turned to radical Islam. Nevertheless, Interior Minister Bernard Cazeneuve said after the claim that a transformation may have happened fast.
Saturday's arrests, which came on top of two others since the killing, including the attacker's wife, concerned his "close entourage", police sources said.
