On 1 June 1999 the PRC Ministry of Public Security started a week-long law-and-order crackdown. Apart from combating crime, the move was even more intended to prevent the 4 June anniversary of the Tiananmen massacre being used as a pretext for "troublemaking" anywhere on the Chinese mainland.
六月一日，中共公安部實施為期一周的「嚴打」，除緊抓治安，目的更在致力防範大陸境內藉六四「鬧事」。