Chad is accusing Sudan of carrying out air strikes on four border villages.
The government says Sudan's air force targeted Chad's villages of Bahai, Tine, Karyari and Bamina, destroying homes and causing panic among residents. Government officials did not say whether there were any casualties.
N'Djamena called on the African Union and the United Nations to condemn the bombings against "peaceful Chadian citizens."
The accusation comes days after Chad accused Khartoum of backing forces with the rebel Union of Forces for Democracy and Development, which attacked two Chadian towns recently.
In another development, the U.N. peacekeeping agency is sending a mission to Chad and the Central African Republic to examine ways of protecting refugees from violence linked to the conflict in Sudan's Darfur region.
The head of U.N. peacekeeping operations, Jean-Marie Guehenno, says one option would be setting up a monitoring operation that would observe the security situation and alert local authorities about cross-border raids by armed groups.
The second option would be to deploy a more robust peacekeeping force that could help protect refugee camps, patrol border areas and facilitate the delivery of humanitarian aid. But, Guehenno says that option would entail considerable challenges, such as persuading U.N. members to contribute troops, and getting approval from Chad's government.
Guehenno told the U.N. Security Council Friday that eastern Chad is now home to more than 200,000 refugees from Darfur, and another 50,000 internally-displaced Chadians.
Thousands of refugees have also fled from Darfur to northern regions of the Central African Republic.
The U.N. official says urgent action is needed to help the refugees, due to escalating rebel violence in the region.
Some information for this report was provided by AP and Reuters.