In the early morning of May 19, the establishment of China's first autonomous trade union, the Beijing Workers' Autonomous Federation, was announced in Beijing. At 9:30am, the Beijing Workers' Autonomous Federation issued the "Capital Workers' Manifesto": "The Chinese Communist Party Central Committee and the State Council must unconditionally, and within 24 hours, accept the two demands of the hunger-striking students. Otherwise, we, the workers of the city, will begin a strike at 12:00 midnight, May 20, for 24 hours; depending on how the situation develops, we will decide on the next steps to be taken." This was also the first time a workers' flag was erected in Tian'anmen Square.

Reference: "The Tiananmen Papers"