At least 3-million Afghans are in "urgent" need of food and could face famine if they do not get help, the UN warned on Monday, as the war-torn country battles the worst drought in living memory.
A dry spell mainly across northern and western Afghanistan has devastated crops, livestock and water supplies, forcing hundreds of thousands of people from their homes.
The drought comes at a terrible time for the country, which is already grappling with a 17-year conflict and is preparing to hold a parliamentary election that is three years late.
"Those people are surviving on less than one meal a day and in all likelihood that meal is bread and tea."
Lanzer said the 3-million people hardest hit were in the "emergency" phase four of a widely used food insecurity index – one level below famine.
The figure was "among the highest in the world" and they needed "the most urgent response", he said.
"If we don’t [reach them] there’s a risk that these people go into level five," Lanzer said.
Aid groups distributed basic commodities, including wheat flour fortified with minerals, oil and lentils, to 600,000 people in September, Lanzer said.
Lanzer said the figures were "far worse than we had anticipated" and he warned the situation could deteriorate as temperatures fall during the winter months.
The drought affecting more than half of Afghanistan was triggered by a huge shortfall in snow and rain last winter.