“The World Health Organization said it will transport via a small UN plane only seven patients with their escorts per flight,” the officials said in a statement carried by Al-Masira channel.

“The number of people signed up for the UN medical evacuations plan is around 32,000 patients with serious illnesses,” Houthis official said.

Critically ill Yemeni children in need of medical care were evacuated from Sana’a on Monday, in what the United Nations said it hopes will be the first of many mercy flights, AFP reported.

Welcoming the start of the humanitarian airlift, the Norwegian Refugee Council (NRC) said that others were handed a “death sentence” when the coalition closed down the airport in Sana’a.

“Today’s move comes too late for thousands of Yemenis who died waiting to leave the country for urgent life-saving care,” said Mohamed Abdi, the NRC’s country director for Yemen.

“We hope that these medical flights will save the lives of other Yemenis. Many more are still waiting to get the health care they need.”

At least 32,000 Yemenis are estimated to have died waiting to get specialized medical treatment abroad according to the Ministry of Health in Sana’a, nrc.no reported.

The medical flights will transport 30 patients to Cairo and Amman with chronic diseases who cannot be treated inside Yemen.

Seven young patients and their families gathered at Sana’a airport, which has been closed to commercial flights since 2016, clutching their transport documents ahead of their journey to the Jordanian capital Amman.

“This is the first of what we hope and believe will be many flights,” UN Resident Coordinator for Yemen Lise Grande said as the first humanitarian flight was prepared to depart from the war-torn country.

“It’s a very important day, it’s a day of hope. It shows that everyone wants the people who need help to get that help,” she told reporters at the airport.

“The key is to have many flights, bigger planes, so that the people who need aid can get to the places where they will receive it.”

UN Special Envoy for Yemen Martin Griffiths last month told the Security Council that “we are very close to seeing the first flight move 30 patients who are now waiting in Sanaa for their treatment”.

The move was among confidence-building measures aimed at ending a five-year war which has left tens of thousands of people dead and displaced millions in what the UN has called the world’s worst humanitarian crisis.

Houthis control swathes of Yemen since a Saudi-backed government fled the country in late 2014. The development caused Saudi Arabia and allies to launch an all-out war on the impoverished country.

The Saudi-led war has triggered the world’s worst humanitarian crisis, with the World Food Programme saying that over 11 million people face a daily struggle to find enough food, and 240,000 people live in famine-like conditions.

In November, the coalition – which controls Yemen’s airspace – said that patients needing medical care would be allowed to be flown out of Sana’a.

One of the children waiting for the evacuation flight, Abdullah Abed, is suffering from kidney failure and needs an organ transplant, his father told AFP.

“Severe diseases in Yemen are many, and people need to travel. The United Nations must operate the air bridge regularly, send abroad patients suffering from diseases, open Sanaa airport, and end the blockade of Yemen”, Abed Ali Murshid said.