A hospital supported by Doctors Without Borders (MSF) has been hit by airstrikes in Yemen, the medical charity confirmed on Monday. At least 11 people were killed and 19 more injured in the incident, MSF said.

The hospital in the Abs district of the northwestern Hajjah province was hit at 3.45pm local time (12:45 GMT), the Paris-based NGO said in a Twitter post, adding that the number of casualties is still unknown.

BREAKING: #Yemen MSF-supported hospital was hit by airstrikes at 15:45. We are assessing the situation. Number of casualties still unknown. — MSF International (@MSF) August 15, 2016

“Yes, we confirm the news. A hospital that is run by MSF was hit by a couple of airstrikes today at 3.45pm local time. Right now we don’t have more information. Medical staff are attending the wounded,” MSF spokesperson Malak Shaher told RT.

#Yemen This is the fourth attack against an MSF facility in less than 12 months. #NotTargethttps://t.co/U2gQHSJ4expic.twitter.com/PdORvBcT7j — MSF International (@MSF) August 15, 2016

MSF confirmed the deaths of 11 people, adding that the number of people injured in the incident had reached 19. The organization also said that nine people were killed immediately in the strike and the other two died later.

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The patients were then evacuated to another hospital, MSF said.

“We called to the Saudi-led coalition and asked them for a window of opportunity ... [for] moving patients. We moved the patients and evacuated the patients to another hospital that we support,” Teresa Sancristoval, MSF desk manager for the Emergency Unit in Yemen told RT.

She condemned the strike urging both parties in the conflict to guarantee the full protection of medical facilities.

“The hospital is a hospital that is identified. We have passed the GPS. I don’t believe in mistakes in the sense that in the war before striking any place you have to be absolutely sure that the harm you’re going to do is justified. Mistake is neglection in a war. When you strike you have to know where you strike,” Sancristoval told RT.

1st aftermath images from Abs hospital. GPS coordinates were repeatedly shared w/ all parties to the conflict #Yemenpic.twitter.com/eP3C77nIFz — Doctors w/o Borders (@MSF_USA) August 15, 2016

“We asked parties of the conflict to guarantee medical space for the patients and for the workers that allow to treat patients and we hope that the last declaration of protection of medical facilities, really, is taken seriously because since it was declared they have still a lot of incidents happening in hospitals, in many places of the world,” she said.

MSF says it has supported the hospital since July 2015, adding that 4,611 patients have been treated at the facility.

At moment of the strike on Abs: 23 patients in surgery, 13 newborns, 12 in pediatric ward https://t.co/U2gQHSJ4expic.twitter.com/5dpJdL98b7 — MSF International (@MSF) August 15, 2016

The incident comes less than two days after MSF accused the Saudi-led coalition of killing 10 children and injuring 28 more in a strike that hit a school in the Houthi rebel stronghold of Saada in northern Yemen.

.@MSF update: Final number of injured from Haydan school is 28 & 10 deaths. All between 8-15 years old #Saada#Yemenpic.twitter.com/Qj4pu8tiPi — أطباء بلا حدود-اليمن (@msf_yemen) August 13, 2016

The coalition denied targeting the school and claimed it hit a rebel camp where underage fighters were trained, AFP reports.

The Saudi-led coalition launched its air campaign in Yemen in March of 2015 at request of Yemeni President Abd Rabbuh Mansur Hadi’s government, which was engaged in a civil war against a Shia Houthi movement that had driven it from the capital. The rebels recognize Abdullah Saleh, who was ousted earlier, as Yemen’s legitimate president.

The coalition has been repeatedly accused of hitting civilian targets. According to a recent UN report, Saudi-led coalition airstrikes were responsible for over 60 percent of 785 child casualties in Yemen in 2015.

The deadliest attack occurred in September of 2015, when 131 people were killed in an airstrike on a wedding in the village of Al-Wahijah. Locals blamed the assault on Saudi Arabia, though Riyadh strongly denied the claim.

In another attack that took place in April of 2015, Saudi airstrikes killed 119 people in a crowded marketplace in the village of Mastaba.

The conflict in Yemen has left 4,300 people dead since March of 2015, half of whom were civilians, according to the UN.