KINSHASA - Surveillance drones could be used by peacekeepers in the rugged hills of eastern Democratic Republic of Congo, the first such deployment of unmanned aircraft in a U.N. mission, as early as June, Congo's prime minister said on Thursday.

The Security Council approved their use last month in Congo's porous and volatile borderlands, where U.N. experts claim a year-old rebellion has received support from neighbouring Rwanda and Uganda, a charge both countries deny.

"The process of acquiring drones has already been launched. By June or July they should be operational," Augustin Matata Ponyo Mapon told reporters after returning from New York where he met Secretary-General Ban Ki Moon.

A spokesman for Congo's U.N. peacekeeping mission, known as MONUSCO, said he was not aware of a deployment date for the drones.

U.N. peacekeeping chief Herve Ladsous told the Security Council in January that aerial systems were needed to monitor an area of rugged terrain, thick forests and possessing few roads. But unlike unmanned U.S. aircraft that have carried out strikes in Pakistan and Yemen, the U.N. drones will not be armed.

The Council said it would be a trial deployment "to enhance situational awareness ... on a case-by case basis" after concerns from Russia, China and Rwanda over the use of aerial surveillance equipment delayed the decision for weeks.

MONUSCO initially asked for surveillance drones in 2008, but the request was never met.

The M23 rebels began taking large swathes of the mineral-rich east early last year, accusing the government of failing to honour a previous peace deal.

They seized and held the eastern city of Goma for 11 days in November, dealing a severe blow to the image of MONUSCO, whose peacekeepers did not intervene to stop the well-equipped force, and reviving interest in the use of drones.

An uneasy truce is now in place, and Uganda is currently hosting talks between Kinshasa and the rebels. But progress towards a negotiated settlement to the crisis in the east, scene of two decades of bloodshed, has been slow.

Matata Ponyo also said that significant advances had been made towards the deployment to the country's east of a 4000-troop strong intervention force agreed by central African nations last year.

The force, composed mainly of soldiers from eastern and southern African nations, will operate under the existing U.N. peacekeeping mandate but is tasked with pursing illegal armed groups.