Yemen's four-year war has set back the country's economic development by 20 years, a top UN official said.
The conflict that began after Iran-aligned Houthi rebels captured the capital Sanaa in 2014 has killed tens of thousands of people and left millions on the brink of famine, according to the UN.
"Progress on socio-economic indicators has been set back by over 20 years and war has brought the country's economy to a halt," Achim Steiner, UN Development Programme administrator, said on Tuesday.
Yemen's civil war has created the world’s worst humanitarian crisis, with nearly 80 per cent of the population, 24.1 million people, requiring some form of humanitarian assistance and protection.
“People are hungry, people are suffering, their institutions, their schools, their local administration have collapsed, and for many of them life as they knew it simply has ceased to exist,” Mr Steiner said.
Before the war, Yemen was already the Arab world’s poorest country.
Mr Steiner toured the country, visiting Aden, rebel held Sanaa and the vital port city of Hodeidah.
“I saw deep sadness…a nation that essentially has lost its ability to develop,” he said.
The UN official said one in every three Yemenis is at a risk of starving to death.
UN condemns Houthi attack on Saada
The UN warning comes after Houthi rebels launched a rocket attack on a busy market in the northern province of Saada on Monday.
Preliminary reports by the UN indicated that 14 people died, including four children.
"An additional 26 people, including 14 children, have been reportedly injured. Several of the wounded are in a critical condition," said the UN, citing reports by local health authorities.
Yemen's government criticised the UN, saying it had failed in the past to condemn Houthi crimes.
But a UN official told The National on Wednesday that the world body had continually condemned violations carried out by the rebels.
Yemeni government officials have called on UN Special Envoy to Yemen Martin Griffiths to condemn the Houthis. The UN official pointed out that his mandate "does not include monitoring of human rights".
The Office of the United Nations High Commissioner for Human Rights has a mandate to comment on human rights violations, the official said.
Lise Grande, the UN Humanitarian Co-ordinator in Yemen, issued a statement late on Tuesday denouncing the attack on Sadaa.
"This is a terrible turn of events. For three months, the number of reported civilian casualties in Saada has been falling," Ms Grande said.
"This is a reversal of everything everyone has been working towards these last weeks and months.
“Ending the fighting and the killing of civilians is the highest priority. Everything must be done to bring peace to Yemen.”