Events in eastern DR Congo remain "alarming," said UN peacekeeping spokesman Kieran Dwyer on Friday, adding that the M23 rebels are in the town of Sake and reported to be pushing further into government-held territory in North Kivu province.

UN officials and diplomats say the national army has collapsed in the face of the rebel advance with hundreds of soldiers reportedly having joined M23 in the past week.

And in what would be a major first for its peacekeeping operations, the UN said Friday it was considering using drones to monitor the fighting between the military and the M23 rebels.

Meanwhile, regional leaders were heading for Kampala for a summit Saturday on the latest crisis in the mineral-rich region.

Over the past eight days, the M23 rebel group has pushed out of their stronghold near the Rwanda border to take the provincial capital of Goma and overthrow government forces in other areas.

The rebels are reported to be moving towards Masisi and the major city of Bukavu in North Kivu.

United Nations backing

The UN has an estimated 6,700 troops in North Kivu backing up government forces under a Security Council mandate to protect civilians.

UN officials say there have also been reports that civilians face targeted killings and abductions by the M23 who have vowed to oust the government of President Joseph Kabila, who is accused of breaking a peace deal from an earlier conflict.

The rebels have had support from Rwanda, according to UN experts but Rwanda's President Paul Kagame strongly denies aiding M23.

The M23 takes its name from the date of a March 23, 2009 peace treaty with the government, where they became a political party in exchange for the release of imprisoned rebels. The M23 whose military leader Bosco Ntaganda is wanted for war crimes by the International Criminal Court.

hc/mr (AFP, Reuters, AP)