Details of the secret plan for Israeli forces to invade the Sinai desert were revealed to the Chiefs of the Defence staff in October. On 29 October Israeli armour, preceded by parachute drops on two key passes, thrust south into the Sinai, routing local Egyptian forces within five days. Affecting to be alarmed by the threat of fighting along the Suez Canal, the UK and France issued a twelve-hour ultimatum on 30 October to the Israelis and the Egyptians to cease fighting. When, as expected, no response was given, Operation Musketeer was launched.