A fierce battle in the eastern suburbs of Damascus has killed more than 160 people in the past two days as rebels struggle to break a months-long blockade by forces whose allegiance lies with President Bashar al-Assad, activists have said.

Fighting began on Friday when rebel units attacked several checkpoints in an area known as the Eastern Ghouta, which has been under siege for more than six months.

According to local and international aid workers, President Assad’s forces appeared to be trying to starve out residents. This latest bloodshed comes as the Oxford Research Group – a think tank – says that a total of 11,420 children have now been killed in the conflict.

Download the new Independent Premium app Sharing the full story, not just the headlines

The report shows that explosive weapons have accounted for more than seven out of every 10 deaths since fighting started in March 2011. Small-arms fire accounts for more than one quarter of the total, with older boys in the 13 to 17-year-old group the most frequent victims of targeted killings. Of the 764 children recorded as summarily executed, 112 were reported to have been tortured, including some of infant age.

With any resolution to the civil war appearing so far stymied, Hamit Dardagan, co-author of the report, said: “This grim and terrible record shows why a sustainable peace, not more bombs and bullets, is the only way to guarantee the safety of children.”