Or the United Nations
Emergency Forces, where instituted after the 1956 Suez Canal
crisis. The troops were stationed to protect the canal and allow free travel by any nation. Although the UN troops didn't do much, besides guard the canal, their mere presence in the Sinai Peninsula
acted as a buffer between the Egyptians
and the Israelis
In May of 1967, after much goading by the Syrians, Egyptian President Gamal Abdel Nasser, evicted UNEF and ordered his own army to take UNEF positions on the peninsula. This move, as well as the blocking of Israeli ships from the canal, were direct reasons for the Six-Day Arab-Israeli War the following month.
Source: Six Days of War: June 1967 and the Making of the Modern Middle East, by Michael B. Oren