Top United Nations officials called on the United States on Thursday to revoke its decision to designate Yemen's Houthi militias a foreign terrorist organization, fearing it would push the country into a large-scale famine.

UN envoy for Yemen Martin Griffiths, in a briefing to the Security Council via videoconference, condemned “in the strongest terms possible” the attack carried out by the Houthis on Aden airport last month.

The attack had intended to target the new Yemeni government upon its arrival in Aden.

“The attack cast a dark shadow over what should have been a moment of hope in the efforts to achieve peace in Yemen. The formation of the Cabinet and its return to Aden was a major milestone for the Riyadh Agreement,” he said.

Griffiths congratulated Yemeni President Abdrabbuh Mansur, “the parties to the Riyadh Agreement, and all political parties and components that supported and contributed to this process."

He also commended Saudi Arabia "for its successful mediation role.”

He said he was “extremely concerned” about the impact of the decision from the US to designate the Houthis as a foreign terrorist organization. “We fear in my mission that there will be inevitably a chilling effect on my efforts to bring the parties together.”

He also feared that “the decision would contribute to the prospect of famine in Yemen and should be revoked based on humanitarian grounds at the earliest opportunity.”

UN aid chief Mark Lowcock said the priority was to prevent “a large-scale famine.”

“Some 16 million people will go hungry this year, and 50,000 are already essentially starving to death, amid a shortfall in aid,” he said. “Another 5 million are just one step behind them,” Lowcock said.

“Yemen imports 90 percent of its food. Nearly all that food is brought in through commercial channels. Aid agencies give people vouchers or cash to buy commercially imported food in the market. Aid agencies cannot – they simply cannot - replace the commercial import system,” he added.

Commercial traders “were not sure they would be able to continue importing food into Yemen in those circumstances.”