Chad denied initial reports by the French embassy on Sunday of a big column of rebels heading for the capital N'Djamena, saying the city's population faced no threat.
"I categorically deny reports that an alleged column of rebels is 400km from N'Djamena," Hourmadji Moussa Doumgor, the Chadian Communications Minister, told reporters, adding that the population "is in no way threatened."
The French embassy in N'Djamena had suggested otherwise earlier in the day, stating "the presence of a large rebel column has been confirmed in the Bata region of the country, heading west," and that fighting around the capital over the next 24 hours "cannot be ruled out."
But the embassy softened its warning in a separate statement later in the day, saying that the column "was no longer progressing."
Earlier, a Chadian military source said the rebels were from the Rally of Democratic Forces (RAFD), which took the towns of Biltine and Am Zoer on Saturday.
Meanwhile, Chadian troops regained control on Sunday of the main eastern town Abeche, after a different rebel group, the Union of Forces for Democracy and Development (UFDD) left during the early hours.
Doumgor, who also serves as government spokesman, accused Saudi Arabia as well as neighboring Sudan, which denies accusations of backing rebels in Chad, of mounting "a large scale operation to destabilize it."
"This operation bears the hand of Sudan and Saudi Arabia," he said. "It's Sudan and Saudi Arabia that are equipping and training mercenaries, and providing them with the necessary logistics to attack Chad today on several fronts in the east," he said.
He alleged that "60 percent" of Nouri's men are "young Wahabites between 13 and 17-years-old ... recruited in the madrasah [Koranic schools] of Jeddah, Mecca and Riyadh."