Chad is repeating accusations that the Sudanese government is supporting rebels trying to topple the Chad government.
The accusations coincide with a decision by the European Union to deploy a security mission in Chad and the Central African Republic in response to the refugee crisis in these countries created by the conflict in Sudan’s Darfur region.
N’Djamena said Khartoum had ordered Chad rebel groups in Darfur to cross the border and attack government forces there, according to AFP.
The Chad government said it has the legitimate right to defend itself.
The Chad air force also attacked rebel position in the east of the country on Tuesday. These were the first known hostilities since early December.
Sudan and Chad are accusing each other of backing rebel groups trying to overthrow the respective governments. The tension between the two countries is exacerbated by the massive influx of refugees into Chad from Sudan’s war-torn Darfur province.
The E.U. on Monday approved the deployment of a force to provide security for civilians and aid workers in Chad and the Central African Republic. The mission will comprise 3,700 troops, mostly from France.
Deployment will begin in March and is expected to reach full capacity by May. The mission will be mandated initially to run for one year.
The conflict in Darfur erupted in 2003 between local rebels and armed groups said to be backed by Khartoum.
According to international organizations, more than 200,000 people have been killed in the Darfur conflict and over 2.2 million displaced.
The Sudanese government is downplaying the death toll in the Darfur conflict, claiming it is closer to 9,000.
The deployment of the E.U. mission has been repeatedly delayed, mainly due to lack of equipment.
The mission will operate in coordination with the joint U.N.-African Union peacekeeping force, expected to be deployed sometime during 2008 in Darfur itself.