A hospital supported by Doctors Without Borders was barrel bombed in Syria, causing seven deaths and the partial destruction of the building, the non-profit organization said.

The "double-tap" barrel bombings occurred first at about 9:40 a.m. on Saturday in a populated area in the town of Zafarana in Syria's northern Homs province. Nearly an hour later, two barrel bombs were dropped at the entrance of the hospital -- injuring 47 patients and medical staff.

"This bombing shows all the signs of a double-tap, where one area is bombed and then a second bombing hits the paramedic response teams or the nearest hospital providing care," Brice de le Vingne, director of operations for Doctors Without Borders, said in a statement. "This double-tap tactic shows a level of calculated destruction that can scarcely be imagined."

Barrel bombs are crude explosive devices filled with oil or forms of shrapnel sometimes loosely dropped from high altitudes via helicopter which may cause indiscriminate damage. The regime of Syrian President Bashar al-Assad has often been accused of carrying out such bombings.

"This makeshift hospital was providing a lifeline of care to around 40,000 people in Al Zafarana town and the surroundings," de le Vingne said. "It is already a tragedy that seven people -- including a small girl -- have been killed, but if the hospital has to close down or reduce activities, that is a double tragedy for the people living under the permanent threat of war, with nowhere else to turn for medical assistance."

Human rights organizations fear medical facilities and doctors are new targets in an apparent escalation of violence amid the Syrian civil war.

Doctors Without Borders -- known officially as Médecins Sans Frontières or MSF -- has sharply condemned strikes against its personnel and buildings.

Several U.S. service members were suspended last week over the bombing of a MSF hospital in Kunduz, Afghanistan, in October. Another MSF-operated hospital in Yemen was destroyed in a missile strike later that month.

Syria has been blighted by a complex civil war in which the Islamic State, the Syrian government and multiple Syrian rebel groups fight for control of territory, causing a mass exodus of migrants seeking refuge elsewhere.

More than 3 million Syrians have fled to Turkey, Lebanon, Jordan and Iraq and nearly 800,000 have reached several countries of the European Union, creating a migrant crisis that's straining economies attempting to cope with the influx of asylum-seekers.

By Andrew V. Pestano