Russia has rejected accusations that it committed war crimes by targeting health facilities in Syria, even as the death toll from airstrikes on hospitals rose and growing condemnation over the Kremlin’s aerial campaign.

“We categorically do not accept such statements, the more so as every time those making these statements are unable to prove their unfounded accusations in any way,” a spokesman for Vladimir Putin said.

France, Turkey and western diplomats have all said the strikes on two locations by forces supporting Syrian president Bashar al-Assad amount to war crimes.

Turkey’s foreign ministry accused Russia of carrying out an “obvious war crime” and warned that bigger and more serious consequences would be inevitable if Russia did not immediately end such attacks.

Turkey’s prime minister, Ahmet Davutoğlu, said: “If Russia continues behaving like a terrorist organisation and forcing civilians to flee, we will deliver an extremely decisive response.”

The international charity Médecins Sans Frontières said 11 people died – five staff members, a caretaker and five patients including a child – after airstrikes on a facility it supports in the province of Idlib. It said the death toll was likely to still rise.