The US government aid agency on Tuesday warned that a humanitarian crisis in conflict-ridden Yemen was being "overlooked" despite escalating to levels seen in the Horn of Africa and the Sahel.
"It's often overlooked.... If you look at the global crises right now, Yemen doesn't get on that list and it really needs to be," Nancy Lindborg, a USAID assistant administrator, told AFP in Rome after a visit to the country.
Five million people need urgent aid and five million more are facing food insecurity out of a population of 25 million people, Lindborg said, adding that the crisis had been "exacerbated" by conflict and a political transition.
The depletion of water resources is a particularly acute problem, she said.
"This is something the government must absolutely find the political will to organise. Otherwise they will be going off a cliff soon," she added.
Lindborg was taking part in a joint visit with the Organisation of Islamic Conference, the Gulf Cooperation Council and the Arab League.
She said the US would be providing an additional $6.5 million (5.2 million euros) in humanitarian aid to Yemen, bringing its total forecast aid budget for this year to $118 million from $115 million last year.
Deadly anti-regime protests swept Yemen last year, finally forcing president Ali Abdullah Saleh to step down in February after 33 years in power.
The political crisis has left the country's economy in tatters and aggravated the dire security situation, with Al-Qaeda militants launching a wave of attacks in the mostly lawless south since Saleh's departure.
Yemen is the poorest country in the Arabian peninsula, with more than 40 percent of people living below the poverty line.