In her first video diary for NBC News, 26-year-old Zein describes life in eastern Aleppo, which has been under siege by government forces for several months.

The United Nations is warning of mass starvation among the region's 250,000 residents, who are cut off from supplies of food, water and medicine.

Zein, who asked not to use her second name, was jailed for just over a year after she participated in anti-government protests.

SPECIAL REPORT: Aleppo's Children Are Dying

Her family have since moved away but she stuck around and got a job as an aid worker with a charity, although they are now running out of supplies to distribute. She has also volunteered at a hospital and a makeshift underground school, where the kids talk longingly of food they can no longer eat.

Aleppo has become the epicenter of Syria's five-year civil war, with rebels in the east encircled by Syrian government forces backed by Russia.

On Tuesday, the Russian military launched renewed strikes involving missiles as well as jets launched from its sole aircraft carrier.