It was from the Egyptian occupation of Palestine (Gaza Strip) from 1948-1967. The Egyptians even made it all the way past Bethlehem in 1948 into the outskirts of Jerusalem (of which there are canceled Egyptian Palestine occupation Bethlehem covers) before being repelled. Also, from late 1956 to early 1957, there are Israeli postmarked and cached covers from its occupation of Gaza and the Sinai during the Suez Crisis which was before the Six Day War in 1967 until stamps were issued by the Palestinian Authority and Hamas in the Gaza Strip from the 1990's onward. See:
http://www.zobbel.de/stamp/occ_poste.htm