Although U.N. investigators did not directly pin the blame for the mishaps on the United States, the report noted that at least two of the unmanned aircraft appeared to be U.S.-manufactured and suggested that Washington had been less than forthcoming about its drone operations in Somalia.
The U.S. military has conducted clandestine drone flights over Somalia for years as part of a broader counterterrorism campaign against al-Shabab, a group of Islamist fighters that controls much of the country and is affiliated with al-Qaeda.
Although the drone missions have long been an open secret, the Obama administration acknowledged last month for the first time that it “is engaged in a robust range of operations to target al-Qaeda and associated forces, including in Somalia.”
The number of military drone flights over Somalia has increased substantially since the Air Force opened a new base last year in next-door Ethiopia. The military opened a similar base in late 2009 in the Seychelles, an Indian Ocean archipelago off the eastern coast of Somalia.
Both of those operations complement a much bigger U.S. military drone base in Djibouti, a small country on Somalia’s northwestern border on the Horn of Africa.
Somalia, a failed state stricken by famine and decades of civil war, has been largely off-limits to U.S. ground troops since 1993, when Somali fighters shot down two military helicopters and killed 18 Americans in the “Black Hawk Down” debacle.
In recent years, however, small teams of Special Operations forces and CIA operatives have gradually stepped up secret missions inside Somalia to rescue hostages and hunt for al-Shabab leaders.
The U.N. Security Council imposed an arms embargo on Somalia in 1992, although it has carved out an exception for an African Union military force that has been battling al-Shabab and propping up a transitional Somali government based in Mogadishu.
The U.N. Monitoring Group on Somalia, which prepared the new report, said that it considered the use of drones in that country “a potential violation of the arms embargo” because the aircraft are “exclusively military” in nature.
The Pentagon has supplied several small, hand-launched surveillance drones, known as Ravens, to the African Union troops in Somalia. But any other drones — such as the Predator and Reaper unmanned aircraft that the U.S. military flies at higher altitudes — would “be operating in violation of the embargo,” said Matthew Bryden, a Canadian official and coordinator for the U.N. Monitoring Group.
Spokesmen for the Pentagon and the State Department declined to comment on U.S. drone operations in Somalia.
The U.S. military has plans to send more surveillance drones to Somalia. Earlier this month, the Pentagon notified Congress that it will give eight additional hand-launched Ravens to Kenyan forces deployed to Somalia as part of the African Union mission.
The U.N. report said that unmanned aircraft now “routinely operate in Somali airspace.” Confirmations are elusive, however, because it can be difficult for people on the ground to distinguish between drones and regular planes flying high overhead.
The United Nations said it had documented 64 unauthorized flights of drones, fighter jets or attack helicopters in Somalia since June 2011.
At least 10 of those flights involved drones, according to the report, which provided dates and locations but few other details. U.N. officials said they catalogued the flights from “confidential international agency security reports” and press reports.
In addition, the U.N. report presented evidence of two other incidents in which aircraft believed to be drones nearly caused catastrophes.
The first occurred Nov. 13, when a small surveillance drone fitting the description of a Raven flew dangerously close to large fuel depots in Mogadishu kept by the United Nations and African Union. U.N. officials said it was unclear who was operating the drone.
The second incident happened Jan. 9, when a drone flying above Mogadishu nearly collided with a Boeing 737 transport plane carrying more than 100 African Union soldiers.
That near-miss prompted the commander of the African Union forces in Somalia to call an urgent meeting with partner countries participating in the peacekeeping mission, according to U.N. officials. They said the commander complained that the unauthorized and uncoordinated drone flights represented a threat to his troops and “aviation safety in general.”
A military spokesman for the African Union force did not respond to an e-mail Monday seeking comment.