Witnesses say an explosion has killed at least five soldiers in the Somali capital, Mogadishu.
Residents say they saw the bodies of three Ethiopian and two Somali government soldiers lying in the street after the attack Tuesday.
The witnesses say Ethiopian troops opened fire after the blast. There has been no word on additional casualties.
Islamist insurgents launch almost-daily attacks on Somali government forces and allied Ethiopian troops. More than a year of fighting has killed thousands of Somalis and displaced hundreds of thousands more, mostly from Mogadishu.
U.N.-sponsored peace talks in Djibouti last week ended with no progress toward an agreement.
Ethiopian troops entered Somalia in 2006 to help the government oust an Islamist movement that had seized power in Mogadishu and other cities.
Somalia has endured more than 17 years of chaos and conflict since the fall of the country's last stable government in 1991.
Some information for this report was provided by AP.