The burnt wreckage of two missing Ugandan military helicopters was found in the Mt. Kenya region, a Kenyan officer said Tuesday.

"The two missing Ugandan helicopters were discovered this morning by a fixed wing aircraft which cannot land there. Already rescue operations are underway to rescue the soldiers," Kenya's military spokesman Bongita Ongeri told Xinhua by telephone.

A third helicopter on the same mission crashed in Mt. Kenya late Sunday, but all seven Ugandan servicemen onboard were rescued on Monday, after they managed to radio for help.

The three gunships and a fourth one on Sunday flew from Entebbe, Uganda, to Mogadishu, Somalia, to boost African Union (AU) forces there battling al-Shabaab, an al-Qaida-linked group.

The fourth helicopter had safely landed at the Kenya Defense Forces' military base in Wajir in northern Kenya.

The AU forces, consisting of troops from Kenya, Uganda and Burundi, are planning an onslaught later this month on Somalia's second biggest city Kismayu, a strategic hub for al-Shabaab operations.