Syrian government air strikes have killed at least 30 people in rebel-held areas of Aleppo, sources in the city told Al Jazeera.

The attacks on Thursday came within hours of a strike on a hospital supported by Doctors Without Borders (MSF), which killed Dr Wasem Maaz, the last remaining pediatrician in the rebel-held part of the city.

Sources told Al Jazeera that government warplanes carried out at least 40 air strikes since the attack on the medical facility and that the dead included at least six children and three women.

As of Thursday evening, rescue workers were continuing to dig through the rubble looking for survivors and bodies.

The areas affected by the attacks included Bustan al-Qasr, Bab al-Hadeed, al-Koba and several others. At least one strike mistakenly hit the the government-held area of Medan, killing six civilians. 

Civil defence members carry a casualty after an airstrike at a hospital in Aleppo [Reuters]

The violence comes amid a breakdown in truce talks between the government and opposition representatives in Geneva.

The bloc representing the opposition at peace talks in Geneva, the High Negotiations Committee (HNC), on Wednesday threatened to boycott the next round of talks unless the government stopped its bombing campaign.

The HNC left formal negotiations last week, saying that it needed a "pause", after at least 40,000 people fled fighting near Aleppo when government forces pressed on with an offensive against rebel fighters there.

The Syrian Observatory for Human Rights, which monitors casualties caused by the war, said 200 people including 50 women and children had been killed since an escalation in government assaults on Aleppo since Friday.

'This should not happen'

Speaking to Al Jazeera from Damascus, Pawel Krzysiek, a spokesman for the Red Cross, said: "There is no neighbourhood [in Aleppo] that has not been touched by the recent fighting."

"This should not happen," he said, adding that the number of medical facilities left in the city had already been not sufficient to handle the more than two million people in the city.

"The eastern part of the city is the part of Aleppo that has been really hit hard by the fighting," Krzysiek said.

"However, on the western side, you feel the mortars [and] there are thousands of people who fled [other parts of Syria] and are living in the proximity." 

With additional reporting by Zouhir Al Shimale in Aleppo

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Source: Al Jazeera