Israel must allow clean water and fuel supplies into Gaza 'before it is too late,' a UN expert warned on Friday, as he called on Israeli authorities to stop using water as a 'weapon of war.' Under international law, intentionally depriving the civilian population of the conditions required to sustain life with the aim of bringing about their destruction is classified as an act of extermination and a crime against humanity, said Pedro Arrojo-Agudo, the UN's special rapporteur on the human rights to safe drinking water and sanitation.