Those affected include an estimated 450,000 Palestinian refugees who remain in Syria after nearly five years of violence that has claimed a quarter of a million lives, according to the UN.
Last week marked the third anniversary of the start of the mass flight of the majority of the 150,000 residents of Yarmouk – the largest Palestinian population center in the country, and home to many Syrians – after rebel forces entered the camp and its central mosque was hit in government airstrikes.
Since then, electricity and water supplies to the camp on the outskirts of Damascus have been cut and a complete siege was imposed by government forces and allied groups in July 2013.
Dozens of the thousands still trapped inside the camp starved to death that following winter, and many more have been killed during clashes and ongoing shelling and strikes on Yarmouk.
In April this year, the camp was infiltrated by fighters with the Islamic State group and various armed factions continue to vie for control of this southern gateway to the capital at the expense of its remaining civilian population.