Government air strikes have hit three clinics in rebel-held districts of Aleppo on Friday, rescue workers and sources in the city said.
One strike on the Al-Marja neighbourhood wounded several people, including at least one nurse, the civil defence, known as the White Helmets, said.
Other medical facilities were destroyed in Bustan Qaser and Al-Qoba.
No deaths were reported after the attacks but at least ten civilians died on seperate strikes in the Bustan Qaser neighbourhood.
The clinic in Al-Marja had been providing dental services and treatment for chronic illnesses for about five years.
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Al Jazeera's Andrew Simmons, reporting from the Syria-Turkey border, said that it had been effectively destroyed in the strike.
"This is a medical centre that deals with chronic illnesses and dental surgery," he said. "But it is being used, obviously every facility possible is being used, for medical treatment in Aleppo right now."
The attack came after the Syrian army said in a statement that a "regime of calm" would be enforced in parts of Latakia and Damascus regions from 1am local time (22:00 GMT) on April 30.
It will last for 24 hours in the Eastern Ghouta region east of Damascus and in Damascus, and for 72 hours in areas of the northern Latakia countryside, the statement from the Syrian Army General Command said.
It did not mention Aleppo.
| The clinic hit on Friday was the second medican facility affected by air strikes this week [Al Jazeera]
'Violence is soaring'
Earlier this week, at least 50 people were killed - including two doctors - when air strikes hit the Al-Quds hospital and a nearby block of flats in the rebel-held Sukkari neighbourhood, according to Doctors Without Borders.
The attack on the hospital, which is supported by Doctors Without Borders, has been roundly condemned by world leaders, including US Secretary of State John Kerry, who said it appeared to be a "deliberate strike".
More than 200 civilians have been killed in Aleppo over the past week as rebels have pounded government-held neighbourhoods with rocket and artillery fire, and the government has hit rebel areas with air raids.
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On Friday, air strikes on rebel-held districts killed two civilians, one of them a child, the Syrian Observatory for Human Rights said.
In Geneva, the UN High Commissioner for Human Rights said the latest reports of civilian deaths in Syria revealed a "monstrous disregard for civilian lives by all parties to the conflict".
In a statement released on Friday, Zeid Ra'ad Al Hussein urged all sides to step back from a return to an all-out war.
The UN official said "the violence is soaring back to the levels we saw prior to the cessation of hostilities" in late February. He added that targeting medical facilities and markets could "amount to war crimes".
Source: Al Jazeera and agencies