Islamic extremists in Nigeria have begun using drones, the country's president says, opening a worrying new front in the region's nearly decade-long fight against Boko Haram and an offshoot linked to the Islamic State.President Muhammadu Buhari announced the development during a meeting on Thursday of countries that contribute troops to a multinational force combatting the extremists.This appears to be the first confirmed use of drones by an extremist group in Africa, according to the World of Drones project run by the Washington-based New America think tank. Its section on non-state actors notes that Libyan rebels are reported to have used drones for surveillance in that chaotic North African nation.Deadly attacks against Nigeria's military are on the rise, with 39 soldiers killed this month alone and another 43 wounded. The extremists' use of drones for surveillance in the country's northeast has proven to be a "critical factor" in the resurgence of attacks, the president said.Nigeria's military has its own, armed drones, as the United States and others and others increasingly use them in West Africa's fight against groups linked to al-Qaida and IS.Extremist organizations have been quickly adopting the use of drones. The Islamic State group in Syria and Iraq last year was found to have a formal drone unit, and Houthi rebels in Yemen have used a drone to strike a Saudi warship, according to the New America project.The assassination attempt against Venezuelan President Nicolas Maduro in August, when two drones loaded with explosives exploded during his speech, set off another round of global fears about the threat of drones in enemy hands."Unfortunately, greater commercial accessibility to (unmanned aerial vehicle) technology will make UAVs more attractive as a delivery method for terrorist attacks," U.S. Air Force Maj. Bryan Card wrote in Air & Space Power Journal this year.