One half the population in 1948-49 (750,000) was expelled.
The massacres happened before the ethnic cleaning. In fact, they were used in the terror tactics used by the Hagana (as well as the Irgun and Stern Gang). Palestinians made up the majority of between eighty and ninety per cent of the total population in the 1920s.
When the Zionist movement started its ethnic cleansing operations in Palestine, in early December 1947, the country had a 'mixed' population of Palestinians and Jews. The indigenous Palestinians made up the two-third majority, down from ninety per cent at the start of the Mandate. One third were Jewish newcomers, i.e., Zionist settlers and refugees from war torn Europe, most of whom had arrived in Palestine since the 1920s. There was no civil war.
From the morning after the UN Partition Resolution was adopted, the 75,000 Palestinians in the city were subjected to a campaign of terror jointly instigated by the Irgun and the Hagana. As they had only arrived in recent decades, the Jewish settlers had built their houses higher up the mountain. Thus, they lived topographically above the Arab neighborhoods and could easily shell and snipe at them. They had started doing this frequently since early December.
My parents told me about other methods of intimidation as well: the Jewish troops rolled barrels full of explosives, and huge steel balls, down into the Arab residential areas, and poured oil mixed with fuel down the roads, which they then ignited.
The moment panicked Palestinian residents came running out of their homes to try to extinguish these rivers of fire, they were sprayed by machine-gun fire. In areas where the two communities still interacted, the Hagana brought cars to Palestinian garages to be repaired, loaded with explosives and detonating devices, and so wreaked death and chaos.
The idea that this was a civil war is laughable.
A range of strategies was used by the Jewish forces to terrorize and demoralize the Arab population in a deliberate attempt to provoke a mass exodus. Radio broadcasts in Arabic warned of traitors in the Arabs' midst, describing the Palestinians as having been deserted by their leaders, and accusing Arab militias of committing crimes against Arab civilians. They also spread fears of disease.
They also talked about the use of loudspeaker trucks. These would be used in the villages and towns to urge the Palestinians to flee before they were all killed, to warn that the Jews were using poison gas and atomic weapons, or to play recorded 'horror sounds' the wail of sirens, and the clang of fire-alarm bells.