BEIJING (AP) — U.S. Secretary of State Mike Pompeo has urged China to disclose the details of people killed, detained or missing during the Chinese military's bloody crackdown on pro-democracy protesters centered on Beijing's Tiananmen Square 29 years ago.

Pompeo released a statement on the eve of the anniversary on Monday of the June 4, 1989, suppression of demonstrations that also called on China to release those who have been jailed for their efforts to keep the memory of the crackdown alive.

Hundreds if not thousands of unarmed protesters and onlookers were killed late on June 3 and the early hours of June 4, 1989, after China's communist leaders ordered the military to retake Tiananmen Square from the student-led demonstrators.

Commemoration of the Tiananmen events remains taboo in mainland China.