NAIROBI (Reuters) -- 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 UN sources said, heightening fears of a regional escalation.
Residents said they were moving towards the conflict zone.
The Rwandan-backed M23 recently captured regional capital Goma in an anarchic and mineral-rich part of Democratic Republic of Congo where wars in 1996-1997 and 1998-2003 drew in outside nations and killed millions, mostly from hunger and disease.
The extra Ugandan deployment north of Goma would raise its numbers there - officially to back Congo President Felix Tshisekedi’s army against another rebel force - to about 4,000-5,000, according to UN sources.
Rwanda also has troops operating in east Congo.
In a region of complex and often-shifting alliances, UN experts say Uganda has also backed the ethnic Tutsi-led M23, which is the latest in a string of Rwanda-backed rebellions to take up arms in the name of Congo’s Tutsis.
Ugandan army spokesperson Felix Kulayigye denied a major new deployment, saying its forces had changed their “posture to offensive defense”, without giving further details.
Congo’s Communications Minister Patrick Muyaya did not respond when asked if more troops had arrived, but stressed the priority of Ugandan soldiers in the area was to fight takfiri terrorists though combat against M23 and Rwandan soldiers was also possible.
Having seized much of North Kivu province, M23 rebels have been consolidating their hold on Goma and moving on Bukavu, a town some 200 km (125 miles) to the south. After meeting resistance from Congolese and Burundian forces, they have said they do not plan to take the city.
Uganda and Rwanda have both entered east Congo in the past in the name of protecting their borders but faced accusations of looting natural resources, especially gold.
Zobel Behalal, a senior expert at the Global Initiative Against Transnational Organized Crime think tank, said eastern Congo is as important for Uganda’s economy as it is for Rwanda’s, and the country would do what it needed to protect its interests.
Adding to concerns over Uganda’s potentially ambiguous position, Muhoozi Kainerugaba, the influential son of Uganda’s president and head of the military, has been publicly supportive of Rwanda’s President Paul Kagame and his government.
In 2022, he referred to M23 as “brothers of ours” fighting for the rights of Tutsis in Congo.