In a statement on Tuesday, the Syrian Network for Human Rights (SNHR) said the fatalities included 206 children and 67 women.
A main opposition stronghold on the outskirts of Damascus, Eastern Ghouta has been under siege by regime forces since December 2012. The blockade has left the area’s 400,000 residents struggling with malnutrition and all healthcare facilities non-operational.
Last week, two Syrian babies breathed their last due to malnutrition caused by the regime blockade.
The NGO said regime forces had launched a military operation in eastern Damascus in February and shut underground tunnels used to smuggle foodstuffs to civilians in Eastern Ghouta.
“This has caused a scarcity in foodstuffs in the area,” it added.
Founded in 2011, the SNHR is a non-governmental independent organization that is a primary source for the United Nations on all death toll-related statistics in Syria, according to its official website.
Syria has been locked in a vicious civil war since early 2011, when the Bashar al-Assad regime cracked down on pro-democracy protests with unexpected ferocity.
Since then, hundreds of thousands of people have been killed and more than 10 million displaced, according to UN officials.