The Pentagon has secretly expanded its global network of drone bases to North Africa, deploying unmanned aircraft and U.S. military personnel to a facility in Tunisia to conduct spy missions in neighboring Libya.

The Air Force Reaper drones began flying out of the Tunisian base in late June and have played a key role in an extended U.S. air offensive against an Islamic State stronghold in Libya.

The Obama administration pressed for access to the Tunisian base as part of a security strategy for the broader Middle East that calls for placing drones and small Special Operations teams at facilities within striking distance of militants who could pose a threat to the West.

U.S. officials said the drones being flown out of Tunisia were unarmed and were principally used to collect intelligence on Islamic State targets in Sirte, Libya, where the United States has conducted more than 300 airstrikes since August.

Officials said they sought access to the base in Tunisia to close a critical “blind spot” for U.S. and Western intelligence services in North Africa, which has become the largest base of operations for IS outside Syria and Iraq.

Obama administration officials say they have tried to position Tunisia as a key counterterrorism partner in the region. Though the drones conduct only surveillance missions, U.S. officials said they could be armed in the future, if Tunisia gives the U.S. permission.

The MQ-9 Reaper drone is being flown from secret bases in Tunisia to counter Islamic State fighters. (Air Force photo)