The UN's humanitarian aid agency is seeking 2.1 billion dollars (£1.7 billion) this year to help people in Yemen, a record-high appeal for the Arab world's poorest country, where thousands have died since violence in an ongoing conflict swelled nearly two years ago.
Some 18.8 million people, or more than two-thirds of Yemen's population, need some form of assistance, and about 10 million of those are "acutely affected" - requiring aid in the form of food, water, healthcare and protection to sustain and save their lives, the UN Office for the Co-ordination of Humanitarian Affairs (OCHA) said.
Yemen has been in the grip of a civil war since 2014, when Shiite Houthi rebels and allied forces swept down from the north and captured the capital, Sanaa.
A Saudi-led coalition with blistering air power has been helping government forces battle the rebels since March 2015.
The conflict is made even more complex because an al Qaida branch holds some territory, and Islamic State is also active there.
OCHA chief Stephen O'Brien said the situation has been worsening in recent months.
"Yemen is one of the most food insecure countries in the world," he told journalists in Geneva, noting that the elderly, mothers and children were especially vulnerable.
"A staggering 7.3 million people do not know where their next meal is coming from.
"If there is no immediate action, and despite the ongoing humanitarian efforts, famine is now a real possibility for 2017."
The announcement marked the formal appeal from the OCHA, which last month estimated needs this year of about two billion dollars.
The OCHA last month estimated that some 10,000 civilians have died in the conflict.
Last year's appeal for 1.6 billion dollars was 60% funded and the OCHA reached 5.6 million people.
This year's target is to help 12 million.
The OCHA's chief for Yemen, Jamie McGoldrick, said the agency has been able to reach all 22 governorates in the country, and about 80% of the territory, stressing that funding is generally a more pressing need than access.