(nytimes) -- The warning by the official, Mark Lowcock, the world body’s coordinator of humanitarian aid, was perhaps the most dire so far regarding the blockade’s effects on what already is one of worst man-made disasters.

Mr. Lowcock spoke at a closed meeting of United Nations Security Council diplomats who have expressed alarm over the deterioration in Yemen, the Arab world’s poorest country.

The Yemen crisis has worsened since the Saudis imposed the blockade on Monday after a missile was fired deep into their territory by the Iran-backed Houthi group, which has been warring with a Saudi-led military coalition for nearly three years.

Despite Saudi Arabia’s assurances that the measure was temporary while it reviews inspection procedures, virtually all humanitarian deliveries to Yemen have been halted, including at least three United Nations airplanes full of emergency supplies.

Mr. Lowcock said the Saudis must immediately allow the entry of food and medicine at all seaports, permit the immediate resumption of air services to the cities of Sana and Aden, and provide an “assurance of no further disruption to these services.”

Without such steps, he said, Yemen will suffer “the largest famine the world has seen for many decades, with millions of victims.”

The World Food Program, the anti-hunger agency of the United Nations, which has been feeding seven million people a month in Yemen, is now unable to do so, Mr. Lowcock said. “What we need is a winding down of the blockade to save the lives of those people.”

The Security Council, which has condemned the missile launching into Saudi territory, took no immediate action regarding the blockade. Ambassador Sebastiano Cardi of Italy, the Council’s president for November, said members called on all parties in Yemen to “provide unhindered access for humanitarian supplies,” a reiteration of the Council’s position.

Earlier Wednesday, 15 humanitarian relief groups expressed alarm in a joint statement that the blockade had imperiled lifesaving assistance to millions of people in Yemen.

The country is struggling with an acute hunger crisis that has affected at least 17 million people, more than a third of them considered close to famine. Yemen also suffering a cholera scourge that has sickened nearly one million.

(Photo: Women waited to fill up cooking gas cylinders outside a gas station amid a supply shortage in Sana, Yemen, on Tuesday. reuters)