Cat Bi (Haiphong) based Douglas B-26 Invaders operated over Dien Bien Phu in March and April 1954 during the siege of Dien Bien Phu. In this period, a massive use of Philippines based USAF B-29s against the Viet Minh heavy artillery, including the potential use of nuclear weapons, was planned by the U.S. and French Joint Chief of Staff as Operation Vulture, but was cancelled by the respective governments, while at the conclusion of the battle, some of the beleaguered French troops managed to escape through the jungle to neighboring Thailand.