Ho Chi Minh was at the time ill with fever, and Vo Nguyen Giap ordered "all soldiers... to stand together, go into battle, destroy the invaders, and save the nation." Eventual French superiority in firepower forced the Viet-Minh to withdraw to mountains 80 miles to the north of the Hanoi. However, it took the French 60 days to gain complete control of the city, which had bought enough time for their enemy to evacuate all of its central offices, as well as most of its main forces.[citation needed] After expunging the Viet-Minh from the city, the French demanded the military surrender of their opponents, but the latter refused. The United States, alarmed at the incident, despatched Abbott Low Moffat on a special mission to Saigon and Hanoi to consider a negotiated referendum. However, the re