ROME (Reuters) - 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 on 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”.

An Italian defense ministry official said late on Monday the agreement would allow defensive missions and not offensive action, such as the attack on a suspected militant training camp in Sabratha, Libya, that killed dozens last week.

Italy will authorize departures from the Sigonella base near Catania only if each mission’s aim is to protect personnel, the ministry official said, adding that no request had yet been made.

LIBYAN CHAOS

Sigonella, in eastern Sicily, is home to a U.S. Naval Air Station as well as a base for the Italian Air Force. It is sometimes used for logistical support for American and other NATO forces.

Renzi said he preferred a diplomatic response to Islamic State, which has faced U.S.-led air strikes on the caliphate it has proclaimed across swathes of Iraq and Syria since 2014.

“But then, if we have proof that there are ‘kamikaze’ attackers preparing potential strikes, naturally Italy will do its part along with all the others,” he said.

Islamic State is exploiting chaos in Libya, where two rival governments have been vying for power since Muammar Gaddafi was overthrown in 2011, to establish bases and conduct raids both in Libya and in neighboring Tunisia.

U.S. officials have been trying to persuade Italy to let them conduct such operations from the Sigonella air base for more than a year, the Wall Street Journal reported.

The U.S. attack last week on a base in Sabratha, near the Tunisian border, targeted Noureddine Chouchane, a Tunisian militant linked to two raids in Tunisia that killed dozens, mostly tourists. The aircraft that carried out that attack took off from a base in Britain.

U.S. officials are pushing for drones destined for offensive operations like the Sabratha strike to take off from Sicily, but Italian officials have balked at that step, fearing domestic opposition, the Wall Street Journal reported.