Sanaa, Feb 9 (IANS): Twenty-four patients were evacuated from Yemen to Jordan on a UN-chartered plane, the second flight of a medical air bridge from the closed airport in Sanaa, a World Health Organization (WHO) source said.

An Ethiopian Airlines plane carrying 24 patients and 25 relatives took off on Saturday, a day after the flight was delayed due to technical issues, the source told Efe news.

The patients needed specialized medical treatment, mainly heart and kidney transplants, cancer treatment or suffered malformation of the spinal cords or the thyroid, according to the source.

WHO launched the medical air bridge operation earlier this week with the first flight carrying seven patients to the Jordanian capital.

More patients will be evacuated on flights to Amman and Cairo, the source added without providing further details.

The air bridge of 'mercy flights' was initially due to be launched in October, but negotiations with the countries involved, including Saudi Arabia, caused delays.

Sana'a is under the control of Houthis, an Iran-aligned rebel group opposed to the internationally recognized government of Abdu-Rabeh Mansour Hadi.

The airspace is in the hands of the pro-Hadi Arab coalition and has remained closed to civilian aircraft since 2016.

Houthi health authorities say that around 32,000 patients need to be airlifted via Sanaa airport for medical treatment abroad.

Fighting broke out in late 2014 when Houthi rebels, backed by Iran, occupied Sanaa and other provinces in the country and dissolved the government.

The battle intensified in 2015 with the intervention of the Arab-led coalition made up of Sunni countries in favour of forces loyal to President Abdo Rabu Mansur Hadi, who is internationally recognized and currently in exile in Riyadh.

Over 24 million Yemenis, around 80 per cent of the war-torn country's population, are in desperate need of humanitarian aid due to the conflict, according to UN reports.