Sensing victory against its Somali Islamist foes, Ethiopia attacked retreating fighters from the air on Tuesday and threatened to seize their stronghold Mogadishu after a week of war in the Horn of Africa.
...The African Union (AU) backed Ethiopia's right to intervene in what analysts saw as a potentially significant endorsement that may embolden Addis Ababa further. Diplomats say Washington has also given Ethiopia its tacit support.
Ethiopia attacks retreating Somali Islamists (Reuters) Dec 26, 2006
Update: U.S. Signals Backing for Ethiopian Incursion Into Somalia (New York Times) December 27, 2006