Italy has agreed to let armed U.S. drones take off from an air base in Sicily on a case-by-case basis for defensive missions against Islamic State militants in North Africa, Prime Minister Matteo Renzi said Tuesday.

"If it is a matter of operations against terrorists, against potential Islamic State attackers, there is a close relationship between us and the other allies, above all the Americans," Renzi said in an interview with RTL radio.

The prime minister, who has repeatedly said Italy would not take part in military strikes in Libya without the express request of a recognized government, said they would be authorized "case by case."