In October 1956, Israeli forces attacked Egypt and occupied the Sinai and the Gaza Strip. A few days later British and French troops landed in the Suez Canal Zone. The United Nations General Assembly called for withdrawal of all foreign forces. At the same time they established the United Nations Emergency Force (UNEF) to supervise the ceasefire and withdrawal. This was accomplished in late December 1956. The Israeli forces left in March 1957. Letters from UNEF members were posted free of charge and the cancel shown was the "postage" This postage was used at later dates from various places.