The facility in Idlib specialised in paediatrics
The medical charity Médecins Sans Frontières (MSF)/Doctors without Borders says a hospital it supported in Syria has been flattened by bombs.
The hospital, which specialised in paediatrics, was destroyed by aerial bombings in Millis town, Idlib on Saturday.
Four hospital staff and nine others - five children and two women - were killed.
MSF says two aerial strikes hit the hospital directly, and two more hit the immediate vicinity at around 2:00pm local time.
The charity says the hospital provided essential care for around 70,000 people in the region.
"The bombing destroyed most of the hospital building, including the operating theatre, intensive care unit, paediatric department and ambulances," MSF says.
"The hospital provided emergency care for over 250 patients per day, many of them women and children."
Since early 2014, MSF had supported the hospital with supplies, technical advice and later with financial support.
"The direct bombing of another hospital in Syria is an outrage," says Wiet Vandormael, manager of MSF operations in north-western Syria.
"We have to admire the courage and dedication of Syrian medics continuing to work in the midst of a war where hospitals are so regularly hit in bombing and shelling attacks - and we have a strong sense of obligation to support them in their essential life-saving work."
"Each time a hospital is destroyed, whether it is targeted or in an indiscriminate attack on civilian areas, it deprives Syrians of another lifeline of healthcare."
This attack comes in an environment of significant mass casualties in Idlib.
In the first six months of the year, the two largest MSF-supported hospitals in Idlib reported seven mass-influxes of wounded - resulting in 294 wounded and 33 dead.
In the month of July alone, MSF says the same facilities dealt with nine mass-influxes of wounded resulting in 466 wounded and 37 dead.
"We repeat our urgent call to all those with influence on the conduct on the war in Syria, including the four out of five UN Security Council permanent members that are participants in the war, to urgently effect change to stop hospitals being hit in the course of the fighting," Vandormael added.