The officials say armed men from the southern secessionist movement attacked a military checkpoint Friday, sparking clashes with troops in Dali. The officials say at least 20 civilians were wounded.
The officials spoke on condition of anonymity because they were not authorised to brief journalists.
The clashes likely were in retaliation for the military firing a shell that landed near a funeral tent in Dali in December, killing 19 people. That sparked renewed fighting in the restive south, where the secessionist movement is strong.