The United Nations is trying to prevent mass starvation in war-ravaged Yemen by increasing its food distribution from 8 million to 14 million people, the World Food Programme (WFP) said Friday.

"Those plans to increase to up to 14 million people are a massive logistical and human undertaking," WFP spokesman Herve Verhoosel acknowledged at a Geneva press conference.

"We will need the support of everybody. Inside and outside Yemen," he said, calling for international donations.

The UN considers Yemen the world's worst humanitarian crisis.

In March 2017, humanitarian experts assessed that 6.8 million Yemenis face a food emergency with acute malnutrition and a rising death rate - only one step away from outright famine.

An new assessment that is scheduled for mid-November is expected to raise the number to 12 million or 14 million people - nearly half of Yemen's population, according to the WFP.

Boosting food aid not only depends on funding, but also on the fighting, Verhoosel stressed.

The WFP is unable to reach a major mill on the Red Sea that could provide flour to 3.7 million people for one month.

The UN agency also urged the warring parties to allow shipments into the embattled port of Hodeida, which handles most of Yemen's imports.

"Ultimately of course the violence must stop to give Yemen a chance to pull back from the brink," Verhoosel said. "Unless it does, this will become a country of living ghosts, its people reduced to sacks of bones."

Yemen has been embroiled in a violent struggle between the Saudi-backed government and Iran-linked Houthi rebels since late 2014.