The United Nations refugee agency says thousands of people from Sudan's Darfur region have fled to neighboring Chad following government attacks on three towns.
The office of the U.N. High Commissioner for Refugees says the agency is sending a team to investigate the situation.
Sudan's army confirmed Friday's military operations in Abu Suruj, Sirba and Suleia. It said it was trying to rid the area of rebels.
A Sudanese army spokesman (Brigadier Osman Mohamed al Aghbash) said many people were killed or wounded in the attacks, but he did not provide figures. Rebels say 200 people were killed.
In other developments Saturday, Sudan signed an agreement with the joint United Nations-African Union mission in Darfur giving the troops a legal framework to govern their operations.
The head of the peacekeeping force, Rodolphe Adada, and Sudan's foreign minister, Deng Alor, participated in the signing ceremony in Khartoum. Alor told reporters that Sudan's government will fully cooperate with the peacekeepers.
Once it is fully operational, the mission, known as UNAMID, will have 26,000 troops and police. It is replacing an A.U. force of seven thousand peacekeepers.
Five years of fighting in Darfur has claimed the lives of some 200,000 people and displaced more than 2.5 million others.
Violence in Darfur broke out in early 2003 when rebels took up arms against the Sudanese government. Rebels said officials in Khartoum had neglected their region.
Some information for this report provided by AP and Reuters.