Chad said it was suspending its efforts to mediate in the conflict in neighboring Sudan's western Darfur region until it withdrew armed men massed along the border.
"If the Sudanese government is concerned about preserving friendly relations between our two countries it must quickly remove the armed elements on its territory arrayed against Chad," said presidential communications director Abderaman Kulamalah.
"Until these measures are taken, there is no question of Chad continuing its mediation" of the conflict in Darfur.
Authorities in Ndjamena last week accused Sudan of seeking to destabilize Chad by supporting a 3,000-strong armed force near their border.
