sentences:  There was sectarian conflict within the British Mandate territory between Palestinian Jews and Arabs commencing in the 1920s, escalating into a full-scale Palestinian civil war in 1947.Taking the side of the Palestinian Arabs, especially following the Israeli Declaration of Independence, the neighbouring Arab countries invaded the by-then former Mandate territory in May 1948, commencing the First Arab–Israeli War.Large-scale hostilities mostly ended with ceasefire agreements after the 1973 Yom Kippur War.