SANAA — Yemeni children in critical need of medical care were evacuated Monday from the rebel-held capital Sanaa, in what the United Nations hopes will be the first of more mercy flights.

Seven young patients and their relatives flew out of Sanaa airport, which has been closed to commercial flights since 2016, aboard a UN-marked plane bound for Amman.

"This is the first of what we hope will be a number of flights in the medical air bridge," UN Resident Coordinator for Yemen Lise Grande told AFP, adding that more patients and their families would travel to Jordan and Egypt in coming days.

"It's crucially important that this first flight has gone," she said of the evacuation program which took months to negotiate.

"All of us feel today that this is a major breakthrough and an indication of hope out of Yemen."

Yemen's internationally recognized government, backed by a Saudi-led military coalition, has been fighting Iran-backed Houthi rebels since 2014 when they seized control of the capital.

In November, the coalition — which controls Yemen's airspace — said patients needing medical care would be allowed to fly out of Sanaa.

The move was among confidence-building measures aimed at ending the five-year war that has killed thousands of people and displaced millions in what the UN has termed the world's worst humanitarian crisis.

The lauch of the "air bridge" is a rare bright spot in Yemen, and a possible step toward reopening Sanaa airport which is a key demand of the Houthis and one of the issues being pursued by UN-led mediators.

'We are overjoyed'

Grande said the youngsters on the plane were suffering from serious conditions including cancer and kidney failure.

"These are heartbreaking cases," she said.

"It is clear there are literally thousands of patients who haven't received the treatment they need because of the blockade... With the first flight we've opened that door."

One of the children on the first evacuation flight, Abdullah Abed, is in urgent need of a kidney transplant, his father told AFP.

"We are overjoyed," Abed Ali Murshid said. "Today is the start of the air bridge that we have been waiting for two years."

"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," he said.

The Houthis on Sunday criticized the plan as inadequate, saying as many as 32,000 patients with serious illnesses were waiting to sign up for medical evacuations.

A World Health Organization spokeswoman told AFP that three more flights have been scheduled for Feb. 4, 5 and 7, bound for Amman and Cairo.

Patients awaiting evacuation include "women and children who suffer from conditions such as aggressive forms of cancer and brain tumours, or who need organ transplants and reconstructive surgeries," the WHO said in a tweet.

The Norwegian Refugee Council welcomed the start of the humanitarian airlift, saying thousands of Yemenis had been handed a "death sentence" when the coalition closed down Sanaa airport.

"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 healthcare they need."

The launch of the evacuations comes against a backdrop of a deterioration in Yemen's conflict, with fierce fighting around Sanaa that erupted after a period of relative calm. — AFP