UNITED NATIONS - UN Secretary-General Antonio Guterres strongly condemned ongoing airstrikes impacting civilians, including those on medical facilities and medical workers, in northwest Syria, his spokesman said Thursday.

On Wednesday, several health facilities were reportedly hit in northwest Syria, including a hospital in Maarat al-Numan, one of the largest hospitals in the area.

Stephane Dujarric, the spokesman, said the hospital in Maarat al-Numan was struck despite that its coordinates had been shared through the UN de-confliction mechanism.

"The Secretary-General reiterates his urgent call for the September 2018 Memorandum of Understanding on Idlib to be upheld," he said, referring to agreement on the de-escalation zone brokered by Russia and Turkey for Idlib in northwest Syria.

Civilians and civilian infrastructure, including medical facilities, must be protected, parties to the Syria conflict must respect their obligations under international humanitarian law, Dujarric said, adding perpetrators of serious violations of international humanitarian law must be held accountable.