Syrian opposition activists say government airstrikes have struck five clinics in the northern province of Aleppo where violence has intensified in recent weeks.

The Britain-based Syrian Observatory for Human Rights said four clinics are now out of service in the provincial capital of Aleppo as well as a fifth in the town of Atareb just west of the city.

Aleppo-based activist Baraa al-Halaby confirmed that five clinics were hit, adding that an infant was killed in a clinic in the Shaar neighborhood in the early hours of Sunday.

Syrian government forces and their allies last week laid a siege to rebel-held parts of Aleppo that has been contested since July 2012.

Residents have been reporting shortages of food in rebel-held parts of the city because of the siege.