The Soviet bloc, not Arab states, was the PLO’s main international backer.
Evidence
While the apartheid regime came increasingly under attack in the very countries to which it looked for sustenance, support for the Zionist regime has also kept growing throughout the imperialist state system, including the Arab state system; it is indicative that the Warsaw Pact countries remained the main international supporters of the PLO throughout the Brezhnevite ‘period of stagnation’ — Aijaz Ahmad, In Theory, 55