The U.N. Security Council on Monday strongly condemned the rebel attack on Chad and gave a green light for France and other countries to help the government repel the rebel force.
The statement was approved after Chad's Ambassador Mahamat Adoum sent a letter to the council appealing to all states "to provide all aid and assistance needed to help it" end the aggression by rebels who he said are attempting "to overthrow its legal government by force."
The council statement "calls upon member states to provide support, in conformity with the United Nations Charter, as requested by the government of Chad."
France's U.N. Ambassador Jean-Maurice Ripert said the council statement calls on member states to provide assistance "to the legal government" to oust the rebels. But he said "I cannot answer" whether France will use provide military help.
"I guess there will be some request from the government of Chad addressed to some member states or to all member states of the U.N. and we'll see," he said. "What is important is that the Security Council allows the member states to do so and to answer the request for help and assistance of Chad."
France, the former colonial power, has a long-standing military presence of about 1,400 troops in Chad.
The rebels arrived on the outskirts of Chad's capital, N'djamena, on Friday after a three-day push across the desert from its eastern border with Sudan. Government forces and rebels clashed for a third day on Monday with gunfire and shelling heard throughout the city, a U.N. official said.
Thousands of people were fleeing the city. Casualties from the fighting in N'djamena were believed to be high, and the violence threatened peacekeeping and aid operations intended to stabilize a wide swath of Africa that borders the war-ravaged Darfur region of Sudan.
Since the outset of the fighting, Chadian officials have repeatedly accused Sudan of backing the rebels. Sudan has repeatedly denied any involvement.
An aide to French President Nicolas Sarkozy said Sunday that Sudan wanted to crush Chadian President Idriss Deby's regime to keep the European Union from deploying a peacekeeping force that is to operate along the volatile border with Darfur.
The Security Council called on states in the region "to deepen their cooperation with a view to putting an end to the activities of armed groups and their attempt to seize power by force."