Yemen is in danger of being engulfed by an "imminent and great big famine" that could affect 14 million people, or around half of the population, the UN's relief chief warned on Tuesday.
Yemen, one of the Arab world's poorest countries, has been embroiled in a devastating power struggle between the Saudi-backed government and the Houthi rebels for almost four years.
Humanitarian coordinator Mark Lowcock said the looming famine could be "bigger than anything any professional in this field has encountered during their working lives," in a briefing to the UN Security Council.
Lowcock acknowledged his previous warnings of famine in the country, but said the situation is "much graver" now.
Continued fighting in the key port city of Hodeida and the further collapse of the country's economy have deepened the humanitarian crisis, Lowcock said.
Lowcock called for a humanitarian ceasefire, increased funding for the aid operation, and a larger and faster injection of foreign exchange into the Yemeni economy through its central bank.
Clashes have blocked off some aid routes and the parties to the conflict continue to violate international humanitarian law.
The UN has recorded more than 5,000 violations since May, including mass civilian casualties and damage to hospitals, electricity and water systems.
In 2015, Saudi Arabia, the United Arab Emirates and other Sunni allies started an air campaign against the Houthis, who were advancing towards the southern Yemeni city of Aden, the temporary seat of the government.
Thousands have been killed in the Yemeni conflict, which has devastated the health care system. The UN has labelled Yemen the world's worst humanitarian crisis.
