The US military has begun flying drone aircraft from a base in Ethiopia, as part of its fight against Islamist militants in neighbouring Somalia.
US officials have confirmed to the BBC that the base, in the southern city of Arba Minch, is now operational.
But they stressed that the remotely-piloted drones were being used only for surveillance, and not for air strikes.
It is part of a growing counter-terrorism presence in the region as the US pursues groups with al-Qaeda links.
The US military has reportedly spent millions of dollars upgrading the remote, civilian airport - from which Reaper drones are now being flown.
The remotely-piloted aircraft can be equipped with missiles and satellite guided bombs.
News of the drone deployment was first reported by the Washington Post late on Thursday. US officials confirmed to the BBC that aircraft were now in Ethiopia.
However, the officials added that the drones were flying unarmed because their use is considered sensitive by Ethiopia's government.
The Ethiopian foreign ministry has previously denied the presence of US drones in the country. On Thursday, a spokesman for the Ethiopian embassy in the US told the Washington Post that remained Addis Ababa's position.
"We don't entertain foreign military bases in Ethiopia," Tesfaye Yilma, the head of public diplomacy for the embassy, told the Post.
The drones are used in a surveillance role against the al-Shabab militant group - based in Somalia, and already the focus of drone missions flown from other bases in the region.