More than 60 health facilities in Syria supported by the Doctors Without Borders (MSF) charity were hit in attacks last year, with a dozen completely destroyed, the group said Thursday.
In a new report, MSF warned Syria's health infrastructure "has been decimated", with frequent aerial assaults and shelling of hospitals and clinics, in violation of international law.
The report comes days after an MSF-supported facility in the northwestern province of Idlib was hit in an air strike that killed 25 people.
MSF did not assign blame for the attack. But the Syrian Observatory for Human Rights, a Britain-based monitor, said it appeared to have been carried out by Russian warplanes participating in an aerial campaign in support of the Syrian government.
The MSF report said 63 facilities it supports in north, northwestern, and central Syria had been hit in a total of 93 aerial and shelling attacks throughout 2015, with 12 completely destroyed.
A total of 83 health workers at the facilities were killed or wounded in the attacks, the group said.
All the facilities supported by MSF are located in opposition-held areas of Syria because the group does not have government permission to work in regime-held regions and does not operate in territory held by the IS group.
The group said several of the incidents were so-called "double-tap" attacks, in which a second strike followed shortly after the first, increasing the chances of casualties among those responding to the initial incident.
"This indicates that in some instances the attacks go beyond indiscriminate violence, using targeted attacks against rescue workers -- including medical responders -- as a method of war," MSF said.
The group did not assign direct blame for the attacks in Syria's increasingly complex conflict.
Since it began with anti-government protests in March 2011, the war has evolved in a multi-front conflict involving the regime, rebels, Kurdish forces and militants.
A US-led coalition is carrying out air strikes against IS group in the country, and since September, Russia has also been waging an aerial campaign in support of the government in Damascus.
More than 260,000 people have been killed in Syria since the war began, including more than 76,000 civilians.
MSF said it recorded the deaths of over 7,000 people at 70 of the facilities it supports in Syria in 2015 alone, with more than 154,000 people wounded.
Between 30 and 40 percent of those casualties were women and children, "indicating that civilian areas were consistently hit by aerial bombardments and other forms of attack," MSF said.
The group noted that its report only covered a fraction of all the health facilities in Syria, and did not account for deaths outside clinics or from war-related issues like malnutrition or lack of appropriate treatment.
"The real situation on the ground is thus likely to be much worse than depicted in this report," it said.
"Medical facilities and staff have routinely been subjected to violence, with the result that large sections of the population have been left without healthcare," the report said.
"The health infrastructure in Syria has been decimated."
The group called for an end to attacks on civilian targets and the protection of medical facilities and staff.