US President Barack Obama on Monday praised recent advances by Somali and African Union troops against Shebab militants, but said it was important to keep up the pressure.

Speaking in the Ethiopian capital Addis Ababa, Obama said the Al-Qaeda-affiliated militants offer nothing but "death and destruction".

"Part of the reasons we've seen this shrinkage of Shebab in East Africa is that we've had our regional teams... with local forces. We don't need to send our own Marines in to do the fighting: the Ethiopians are tough fighters and the Kenyans and Ugandans have been serious about what they're doing," Obama said.

 "We've got more work to do we have to now keep the pressure on," he said.