DUBAI: The Saudi-led coalition expressed deep regret over a decision by Medecins Sans Frontieres (MSF) to evacuate staff from northern Yemen and said it was trying to set up "urgent meetings" with the medical aid group.

MSF said on Thursday it was evacuating its staff from six hospitals in northern Yemen after a Saudi-led coalition air strike hit a health facility operated by the group killing 19 people.

"The coalition to support the legitimacy in Yemen expressed its deep regret over MSF decision to evacuate its staff from six hospitals in northern Yemen and asserts its appreciation for the work the group is undertaking with the Yemeni people in these difficult circumstances," the coalition said in a statement carried by Saudi state news agency SPA.

The coalition said it was committed to respecting international humanitarian law in all its operations in Yemen and had set up an independent team to investigate incidents in which civilians are killed.

"The coalition is seeking to hold urgent meetings with MSF to find a way on how to jointly find a solution to this situation," the statement said.

MSF is one of handful of international medical aid groups operating on the ground in Yemen where a 16-month civil war between a Gulf Arab coalition and rebel forces has killed more than 6,500 people and brought one of world's poorest countries close to famine.

Dozens of Saudi-led air strikes and shells launched by the Houthis have hit civilians in Yemen since the Arab coalition began military operations in March 2015 to restore President Abd-Rabbu Mansour Hadi to power.

MSF said many of these attacks had struck health facilities, putting patients and staff in danger and displayed a failure by warring parties to control the use of force.

A coalition air strike on Tuesday hit a hospital operated by MSF in the northern Hajja province killing 19 people, including one of its staff members, and injuring 24, the group said.

On Saturday, an air attack hit what MSF described as a school in neighbouring Saada province, killing 10 children.

United Nations Secretary-General Ban Ki-moon condemned the air strike and called for a investigation, which the coalition said it would conduct.

MSF said it had met with officials from the Saudi-led coalition and shared GPS coordinates of the hospital it operates in with parties involved in the conflict but aerial bombings had continued.

"The decision to evacuate the staff from a project is never taken lightly but in the absence of credible assurances that parties will respect the protected status of medical facilities there may be no other option," said the statement.

The cost from damage to infrastructure and economic losses in the civil war is more than $14 billion so far, according to a confidential report seen by Reuters.