At least 20 people were killed in airstrikes on a hospital in a rebel-held area in the northern Syrian city of Aleppo, activists said Thursday.
Warplanes hit the al-Qudos hospital in Aleppo's al-Sukari neighbourhood late Wednesday, the Syrian Observatory for Human Rights said.
The dead included three children and Wassim Mouaz, the last pediatrician in the district, Rami Abdel-Rahman, the head of the Britain-based Obsevratory, told dpa.
He added that the hospital is now out of service after suffering 14 strikes.
A local member of the non-governmental group, the White Helmet Civil Defence, said that the bombardment hit the hospital and buildings housing medical staff.
"There are many people still missing under the rubble. We expect the death toll to reach 50," the volunteer, who goes by the name of Abdel-Rahman, told dpa.
The identity of the warplanes that carried out the strikes was not immediately known.
The latest deaths have raised to at least 139 the number of people killed by violence involving regime forces and rebels in Aleppo city since April 22, according to the Observatory.
The fatalities included 22 children, added the watchdog that relies on a network of activists inside Syria.
Aleppo, Syria's pre-war commercial hub, is divided between a government-held western sector and the rebel-held east.
In recent months, regime military advances, backed by Russian airstrikes, have put the east - already devastated by years of shelling and air raids - at risk of siege.
International mediator Staffan de Mistura Thursday called on the United States and Russia to urgently help salvage a major truce in Syria and UN-sponsored talks aimed at ending the country's war.
The US-Russian-brokered ceasefire went into effect in February.
But a surge in recent weeks in Syria's violence has made the truce all but collapse.