AFRIN, Syria (AP) -- The death toll from an artillery strike on a hospital in northern Syria has risen to at least 15, medical officials said Sunday. The shelling, a day earlier, caused widespread destruction and knocked out the hospital's maternity ward and surgery unit.

It was not immediately clear who was behind the attack that also wounded 43 and came from areas where both government troops and Kurdish-led fighters are deployed.

Al-Shifaa hospital is in the northern town of Afrin, in an area controlled by Turkey-backed Syrian opposition fighters. Much of the ceiling of the facility collapsed, and electricity cables dangled in a main corridor. The delivery room, the children's section, and the first aid hall suffered the most -- leaving hospital beds covered with rubble.

Blood stained the floor of one debris-filled room, while a mangled wheelchair and a soiled stretcher were piled up in an operating theater.

The hospital director, Dr. Hussam Adnan, said two shells damaged the maternity ward and the surgery unit, while a rocket hit the clinics. The hospital had been crowded at the time of the shelling, and patients and the wounded were evacuated to other hospitals.

"This was a condemned terrorist act that targeted civilians," said Adnan, adding that the hospital serves the town of Afrin and its countryside, an area home to about 350,000 people. Over 350 births take place every month at the hospital, all free of charge, he said.

Adnan and the Syrian American Medical Association -- an aid group that assists health centers in opposition areas -- said two hospital staff members were killed. SAMS also said 11 of its staff were injured, including a midwife seriously.

SAMS called for an investigation into the attack, adding that the coordinates for the hospital, also financed by USAID and the United Nations, had been shared as part of a U.N.-led mechanism to unwind the conflict.

In a statement, the U.S. State Department condemned the attack, saying it was part of a a recent escalation of violence in the area. It called for a nationwide cease-fire in Syria.

"This barbaric attack took the lives of children, medical staff, and first responders. Civilians and civilian infrastructure, including hospitals, must never be the target of military action," it said.

On Saturday, the governor of Turkey's Hatay's province blamed the attack on Syrian Kurdish groups. The U.S.-backed Kurdish-led Syrian Democratic Forces strongly denied claims that it was behind the shelling.

Turkey and allied Syrian fighters took control of Afrin in 2018 in an operation that expelled local Kurdish fighters and displaced thousands of Kurdish residents. Ankara considers the Kurdish fighters who were in control of Afrin to be terrorists. Since then, there have been several attacks on Turkish targets in the area.