New York - The United States said on Thursday it will spend another $575m to help the millions facing starvation and violence amid wars and unrest in Yemen, South Sudan, Nigeria, and Somalia. "This additional funding brings the total US humanitarian assistance to nearly $2.5bm for these four crises since the beginning of Fiscal Year 2017," the US Agency for International Development announced.Mark Green, head of USAID, announced the new funds at the UN General Assembly in New York, where envoys and world leaders have heard about the extraordinary suffering in states stricken by war."Tens of millions of people are in need of humanitarian assistance as a result of the man-made crises in South Sudan, Nigeria, and Yemen, all of which are driven by conflict, and Somalia, where ongoing conflict is exacerbating the effects of a severe drought," it said. "While a swift influx of aid helped roll back famine in some areas of South Sudan, and has so far prevented famine in Yemen and Somalia, life-threatening hunger is spreading in both scope and scale." US President Donald Trump has complained that the United States pays an unfair share of the burden of UN-led aid missions, and a policy review is underway, but officials say funding for the most critical and effective measures will continue.