By 1974, Lon Nol's government had lost a great deal of support, both domestically and internationally. In 1975, the troops defending Phnom Penh began discussing surrender, eventually doing so and allowing the Khmer Rouge to enter the city on 17 April. There, Khmer Rouge soldiers executed between 700 and 800 senior government, military, and police figures. Other senior figures escaped; Lon Nol fled into exile in the US. He left Saukham Khoy as acting president, although he too fled aboard a departing US Navy ship just twelve days later. Within the city, Khmer Rouge militia under the control of different Zone commanders clashed with one another, partly as a result of and partly due to the difficulty of establishing who was a group member and who was not.