UNITED NATIONS, Dec 26 (Reuters) - The U.N. Security Council scheduled an emergency meeting on Tuesday on the conflict in Somalia after a week of fighting between Somali Islamists and interim government forces backed by Ethiopia. The 15-nation council was due at the 3 p.m. (2000 GMT) session to be briefed on the crisis by Secretary-General Kofi Annan's special envoy for Somalia, Francois Lonseny Fall of Guinea, U.N. spokesman Farhan Haq said.