M23's reported connections with Uganda and Rwanda complicate a resolution in eastern Congo.
Some 100 Special Forces soldiers are advising and training regional troops searching for Joseph Kony, leader of the Lord's Resistance Army, in central Africa.
Somalia's president has condemned Kenya's surprise 10-day-long attack onto Somali soil. Uganda has praised it, and the US and French governments claim no involvement.
Somalia's Islamist militant group Al Shabab now controls much of the country, and it has made viable threats against neighbors Uganda, Burundi, Ethiopia, and Kenya.