Li Dazhao
On March 17, 1926, Feng Yuxiang's "Guominjun" troops at Dagu Fort near Tianjin exchanged fire with Japanese warships carrying Zhang Zuolin's Fengtian troops. Japan accused the Chinese government of violating the Boxer Protocol and, with the other seven Boxer Powers, issued an ultimatum demanding the removal of all defenses between Beijing and the sea as set forth under the Protocols. The ultimatum provoked student protests in Beijing that were jointly organized by the left-wing Nationalists and Communists. Two thousand students marched on Duan Qirui's executive office and called for the abrogation of the unequal treaties. Police opened fire and killed over 50 and wounded 200 in what became known as the March 18 Massacre. The government issued warrants for the arrest of Nationalists and Communists including Li Dazhao, who fled to the Soviet Embassy in the Legation quarters. Within weeks, Feng Yuxiang was defeated by Zhang Zuolin and Duan's government fell. After Zhang took power on May 1, 1926, both the Nationalists and Communists were driven underground. A year later, Zhang Zuolin raided the Soviet Embassy in the Legation and seized Li Dazhao. Li and 19 others Communist and Nationalist activists were executed in Beijing on April 25, 1927.