Amid continuing uncertainty over the impact of deep cuts in United States funding for humanitarian work worldwide, the head of the United Nations program coordinating the fight against HIV/AIDS warned on Monday that an additional 6.3 million people will die over the next four years if support is not restored. Several UN agencies have also recently warned that the radical cut in US support - on top of chronic underinvestment in humanitarian work worldwide - is putting millions of lives at risk across the globe.