The Pentagon is shifting its drone operations from a US base in Djibouti to a more remote airfield after local officials voiced concern about possible collisions with commercial aircraft, officials said Wednesday.

"There was a concern over what would happen if a MQ-1 (Predator drone) obstructed a runway, and that it would have a significant impact on commercial air operations," said the official, who spoke on condition of anonymity.

After the attacks of September 11 2001, Camp Lemonnier -- located next to the Djibouti international airport -- took on crucial strategic importance for Washington as a site for stationing special operations forces and drones for assaults on Al-Qaeda militants in Yemen and Islamist Shabab forces in Somalia.

But after five accidents involving MQ-1 Predators since January 2011, the government of Djibouti demanded the Americans halt the drone flights out of Camp Lemonnier, where about 3,000 US troops are deployed, said the defense official, confirming a report in the Washington Post.

Under an agreement with Djibouti, the US military will move its drone fleet from Camp Lemonnier to Chabelley airfield, about 10 kilometers southwest of the capital, according to a document from Congress authorizing defense spending for 2014.

Lawmakers are "aware that the government of Djibouti mandated that operations of remotely piloted aircraft (RPA) cease from Camp Lemonnier, while allowing such operations to relocate to Chabelley Airfield, Djibouti," it said.

The decision to shift flights to Chabelley raised questions about Pentagon plans to spend $880 million to improve the infrastructure at Camp Lemonnier.

The US government plans to invest $13 million for infrastructure at Chabelley airfield to support the drone flights, according to the document. But lawmakers wrote that they remained concerned about how operations at the new location would be sustained over the long-term and at what cost.

The move from Camp Lemonnier to Chabelley has been under discussion for more than six months, the defense official said.

"We have a really strong relationship with Djibouti... And this was a way to accommodate Djibouti in a mutually beneficial way," the official said.

The official said the move might have some temporary, minor effect on current military operations in the region, but there would "no significant operational impact."

Other US military aircraft, including cargo planes and fighter jets, would continue to fly out of Lemonnier, he said.

The French military also uses the airfield at Lemonnier for about a dozen aircraft based there.