Leading Muslim clerics joined Gulf Arab leaders on Friday in condemning a truck attack that killed at least 84 revellers in the Mediterranean resort of Nice on France's national holiday.
Egypt's top Muslim cleric Shawki Allam condemned the assailant as an "extremist" who "follows in the footsteps of the devil."
"Islam never called for the spilling of blood," Allam said in a statement.
"People who commit such ugly crimes are corrupt of the earth, and follow in the footsteps of Satan... and are cursed in this life and in the hereafter."
The six Gulf Arab states issued a joint statement saying that they "strongly" condemned the "terrorist" act in Nice.
"The Gulf Cooperation Council states stand in solidarity with the French republic following this cowardly criminal incident whose perpetrators have been stripped of all moral and human values," the bloc's secretary general, Abdullatif al-Zayani, said.
Regional heavyweight Saudi Arabia issued its own statement condemning the "heinous terrorist" act, adding that it stands in "solidarity" with France and will "cooperate with it in confronting terrorist acts in all their forms."
United Arab Emirates Foreign Minister Sheikh Abdullah bin Zayed al-Nahyan said: "This heinous terrorist crime makes it imperative for all to work decisively and without hesitation to counter terrorism in all its forms and manifestations."
Both Saudi Arabia and the UAE are members of a US-led coalition which has carried out an air war against the Islamic State jihadist group in Syria alongside France.
At least 84 people were killed when a gunman rammed a truck through a crowd of thousands celebrating Bastille Day on the French Riviera on Thursday evening. Scores more were wounded, 18 of them critically.