Six people from the same family were killed in airstrikes by the Syrian regime on the opposition enclave of the divided city of Aleppo, a monitoring group reported Sunday.

The victims, including four children, were killed overnight when helicopters dropped indiscriminate barrels packed with explosives on the rebel-held neighbourhood of al-Sakhour in eastern Aleppo, the Syrian Observatory for Human Rights added.

The toll raised to 54 the number of civilians killed by regime airstrikes and artillery in eastern Aleppo over the past 24 hours, the watchdog said.

The Syrian government has intensified its attacks on eastern Aleppo since Tuesday in an attempt to dislodge opposition fighters from the area.

Some local activists said that this week’s regime attacks were supported by airpower from its allied Russians, a claim that Moscow has denied.

An estimated 300,000 people are under a government siege on the eastern part of Aleppo, where residents report declining or disrupted supplies of basic necessities, including food, water, electricity and medicine.

Once Syria’s commercial hub, Aleppo has been divided into a government-controlled west and an opposition-held east since fighting erupted for control of the city in mid-2012.