BEIRUT >> Airstrikes hit two hospitals and a school in northern Syria, killing and wounding dozens of people today, according to opposition activists, who said the strikes were carried out by Russian warplanes supporting a major advance by government troops.

An airstrike in the province of Idlib destroyed a makeshift clinic supported by the international aid group Doctors Without Borders, while in the neighboring Aleppo province, a missile struck a children’s hospital in the town of Azaz, killing at least five people and wounding dozens. A third air raid hit a school in a nearby village, killing seven and wounding others.

Doctors Without Borders — also known by its French acronym MSF — said in a statement that the hospital in the town of Maaret al-Numan was hit four times in at least two attacks that were minutes apart. It said at least seven people were killed and at least eight others were “missing, presumed dead.”

“This appears to be a deliberate attack on a health structure, and we condemn this attack in the strongest possible terms,” said Massimiliano Rebaudengo, MSF’s mission chief. “The destruction of the hospital leaves the local population of around 40,000 people without access to medical services in an active zone of conflict.”

The aid group said the hospital had 30 beds, 54 staff members, two operating theatres, an outpatients department and an emergency room. MSF has been supporting the hospital since September and covered all its needs, including providing medical supplies and running costs, it said.

The Britain-based Syrian Observatory for Human Rights said Russian warplanes targeted the makeshift hospital, destroying it and killing nine people. The opposition group, which tracks both sides of the conflict through sources on the ground, said dozens were wounded in the attack.

Syrian troops have been advancing in the north under the cover of Russian airstrikes in recent weeks. The offensive has been focused on Aleppo province, where troops are trying to cut rebel supply lines to Turkey and surround rebel-held parts of Aleppo city, once Syria’s largest.

On Monday, Syrian state TV reported that pro-government gunmen have entered western parts of the northern town of Tel Rifaat, where they were fighting “fierce battles’ against insurgents. Tel Rifaat is a major stronghold of militants fighting to overthrow President Bashar Assad.

Opposition activist Yahya al-Sobeih, speaking by phone from Maaret al-Numan, said “the entire building has collapsed on the ground. He said five people were killed near the MSF clinic and “all members of the medical team inside are believed to be dead.”

Paramedics and volunteers were working on removing the rubble, he added. The four-story building was once a cement company, but had served as a makeshift clinic during the war, al-Sobeih said.

The missile attack in Azaz, near the Turkish border, killed five people at the hospital, including three children and a pregnant woman, and wounded more than 30, the Observatory said. Activist Bahaa al-Halaby, who is based in the northern city of Aleppo, said the hospital was struck by a missile, and that 10 people were killed.

Abdulrahman Al-Hassan, chief liaison officer at the Syrian Civil Defense, a group of first responders known as the “White Helmets,” said the women’s hospital in Azaz was hit by two surface-to-surface missiles. He added that some 10 people were killed and many were wounded.

“We think it is Russia because the photos of the missiles have Russian language (and) because we haven’t seen this kind (of missiles) before the Russian intervention,” he said.

Russia has been a key ally of Assad throughout the five-year uprising and civil war, and began launching airstrikes to support his forces on Sept. 30.

In Turkey, the private Dogan news agency reported that more than 30 of those wounded in Russian airstrikes in Azaz, primarily children, were transferred to a hospital in southern Turkey. It showed footage of ambulances arriving at the Kilis State hospital, medics unloading children on stretchers and a girl wrapped in a blanket.

“They hit the school, they hit the school,” wailed a Syrian woman who was unloaded from an ambulance onto a wheelchair.

The Observatory and al-Halaby said an air raid struck a school in the village of Kaljibrin, near Azaz. Al-Halaby said the raid killed seven people and wounded others. The Observatory said five were killed.

Meanwhile in Brussels, European Union officials on Monday called on Turkey to halt its military action in Syria after Turkish forces shelled positions held by a U.S.-backed Kurdish militia over the weekend.

The EU’s foreign policy chief, Federica Mogherini, said that “only a few days ago, all of us including Turkey, sitting around the table, decided steps to de-escalate and have a cessation of hostilities.”

She said more fighting “is obviously not what we expect.”

Dutch Foreign Minister Bert Koenders, whose country holds the EU’s rotating presidency, said “we have the plan for a cessation of hostilities and I think everybody has to abide by that.”

Syria’s main Kurdish faction, the People’s Protection Units or YPG, has been highly effective in combating the Islamic State group, but Turkey views it as a threat because of its ties to the Kurdistan Workers’ Party, or PKK, which has waged a decades-long insurgency against Ankara.

Turkish Prime Minister Ahmet Davutoglu on Monday said the cross-border shelling has succeeded in halting a Kurdish advance on Azaz and vowed the “harshest reaction” if the YPG march on the town again.

Kurdish-led forces had recently gained ground along the border with Turkey at the expense of Syrian rebels, who have been struggling to hold ground amid the massive Russian-backed government offensive.

Also Monday, Syria’s pro-government Al-Ikhbariya TV said one of its correspondents was wounded in a missile attack in the coastal province of Latakia. It said journalist Mazem Mohammed was in stable conditions.