The report, “The Nightmare Returns: Karen hopes for peace and stability dashed”, was to be released at 1pm at the Seven Fountains Centre on Huey Kaew Road, accompanied by an exhibition and panel discussion.
“But police told us this morning we couldn’t hold the event,” a representative of the Karen Peace Support Network said, speaking on condition of anonymity.
“They give no reason. They just said we couldn’t do it.”
In the report, the Karen ethnic community urges the Myanmar military to honour the Nationwide Ceasefire Agreement.
It says more than 1,500 government troops had crossed into areas controlled by the Karen National Union.
Authorities in Chiang Mai could not immediately be reached for comment.