Aljazeera-- The Arab world's poorest country has endured nearly three years of war between Houthi group and Saudi-backed forces.

The conflict is having a devastating impact, causing widespread food shortages and a major cholera outbreak as well as leaving millions in need of humanitarian assistance.

"The situation in Yemen - today, right now, to the population of the country - looks like the apocalypse," Mark Lowcock, the UN's under-secretary-general for humanitarian affairs and emergency relief coordinator, said on Friday.

"The cholera outbreak is probably the worst the world has ever seen with a million suspected cases up to the end of 2017."

Lowcock said "a terrible new epidemic" of diphtheria, a bacterial disease which should be completely preventable by immunisation, has already "affected up to 500 people with dozens and dozens of deaths" in the past few weeks

"That is going to spread like wildfire," he added.

"Unless the situation changes, we're going to have the world's worst humanitarian disaster for 50 years".