A number of people have been killed after airstrikes hit three hospitals in northern Syria, doctors and witnesses say.
According to Medecins Sans Frontieres (MSF), seven people died in an attack in Maarat al-Numan. Activists said another hospital in the town was also hit.
Another strike in Azaz near the Turkish border killed 10, reports said.
MSF blamed pro-Syrian government forces for the raid in on its hospital; Turkey blamed Russia for the Azaz strike.
They come days after Russia and other world powers agreed to a limited cessation of hostilities in Syria.
Almost five years of civil war in Syria have led to the deaths of more than 250,000 people. More than 11 million people have been displaced.
However, Mego Terzian, president of MSF France, said the Maarat al-Numan strikes were carried out by forces “loyal to President Bashar al-Assad”.
Mego Terzian told Reuters: “There were at least seven deaths among the personnel and the patients, and at least eight MSF personnel have disappeared, and we don’t know if they are alive.”
Turkish PM Ahmet Davutoglu said a Russian ballistic missile had hit buildings in Azaz, with children among the dead.
Associated Press reported that five people had died at a children’s hospital.
One doctor, Juma Rahal, told the Reuters news agency: “We have been moving scores of screaming children from the hospital.”
Several more people were killed in an air raid on a nearby village, AP reported.
Russia has been carrying out air strikes in Syria since September in support of President Assad and against what it terms “terrorists”.
Azaz has seen an influx of thousands of people fleeing advances by the Russian-backed Syrian army in Aleppo province.
The Kurdish YPG militia, which has been making advances in the area, has also targeted Azaz.
Turkey has shelled Kurdish positions since the weekend and on February 15 promised the “harshest reaction” if the forces tried to take Azaz.
Turkey views the YPG militia in Syria as allied to the outlawed PKK, which has carried out a decades-long campaign for Kurdish autonomy within Turkey.
Syria said the Turkish shelling was a violation of its sovereignty and has called on the UN Security Council to act.
MSF said four rockets had hit the hospital in Maarat al-Numan, a rebel-held town about 20 miles south of the city of Idlib, within minutes of each other on February 15.
The Syrian Observatory for Human Rights, a UK-based group which relies on a network of sources on the ground, said nine people were killed, including a child. The raid also left dozens of others wounded, it added.
MSF’s head of mission in Syria, Massimiliano Rebaudengo, said the strikes appeared to be a “deliberate attack on a health structure”, warning the attack left tens of thousands without medical care.
Another hospital in Maarat al-Numan was also hit, opposition group the Local Co-ordination Committees said, killing three people.