Sudan has ordered three diplomats from Chad to leave the country within 72 hours, saying the individuals were "persona non grata", the Sudanese state news agency reported on Sunday.
The move by Sudan follows Chad declaring four Sudanese diplomats at the Sudanese embassy in N'Djamena as unwelcome a day earlier, the agency added.
The term persona non grata is used when a foreign diplomat is asked by a host state to be recalled to their home country.
Chad said its decision was due to what it called "grave statements" by Sudanese officials accusing it of interfering in the conflict in Sudan.
