Uganda has deployed more than 1,000 extra soldiers into east Congo in the last week near an area where the Kinshasa government is fighting M23 rebels, four diplomatic and U.N. sources said, heightening fears of a regional escalation.

M23 is the latest in a series of Tutsi-led rebellions that have emerged in Congo's east since the official end of a string of conflicts between 1996 and 2003 that sucked in most of Congo's neighbouring countries and killed 6 million people, mostly from hunger and disease.