Yemen’s 20-month war has killed more than 7,000 people and wounded nearly 37,000, the World Health Organization said, as the UN envoy voiced alarm over the worsening humanitarian situation.

“More than 7,070 people have been killed and over 36,818 injured” as of October 25, the WHO said in a statement.

Another 21 million people are in need of urgent health services, the UN health agency said.

Yemen has been rocked by fighting between Iran-backed rebels and government forces supported by a Saudi-led coalition since March 2015, months after the insurgents seized Sanaa and advanced across the country.

The UN envoy Ismail Ould Cheikh Ahmed urged the coalition controlling Yemen’s airspace to allow commercial flights into and out of Sanaa’s international airport to evacuate the wounded.

The coalition argues that the rebels would use the airport, completely under their control, to transport weapons.

International organisations have also warned in recent weeks of a spread of disease and growing malnutrition rates in the country.

The WHO said 2.1 million people have been internally displaced by the conflict.

More than half of all health facilities across the country have been shut or are functioning only partially amid “critical shortages” in doctors, it said.

Ould Cheikh Ahmed warned of a “very dangerous” health situation with an estimated 2,241 suspected cholera cases.

The UN has confirmed 71 cases of the disease, which is transmitted through contaminated drinking water and causes acute diarrhea.

Attempts by the UN envoy to convince the warring parties to commit to a ceasefire and resume peace talks have failed.