The humanitarian situation in the besieged eastern suburbs of Damascus is "an outrage" and the conflicting parties must allow food and medicine to reach the at least 350,000 trapped Syrians, U.N. High Commissioner for Human Rights Zeid Ra'ad Al Hussein said Friday.

"The shocking images of what appear to be severely malnourished children that have emerged in recent days are a frightening indication of the plight of the people in Eastern Ghouta, who are now facing a humanitarian emergency," Zeid said in a statement.

"I remind all parties that the deliberate starvation of civilians as a method of warfare constitutes a clear violation of international humanitarian law, and may amount to a crime against humanity and/or a war crime," Zeid said.

Zeid's office had a list of several hundred people who needed medical evacuation, but the government had reportedly imposed severe restrictions on such evacuations, leading to the deaths of several civilians, the U.N. statement said.

The U.N. considers the siege and the deprival of water and food a war crime. However, there has been no successful attempt to break the siege. A U.N. convoy last reached the besieged area on Sept. 23, with aid for 25,000 people.

The four-year siege on Eastern Ghouta has led to the deaths of as many as 397 civilians, including 206 children and 67 women, due to a lack of food and medical supplies, Anadolu Agency (AA) reported.

Since the Syrian civil war began in 2011, sieges and starvation have been used as tools of war. Placing cities under siege and cutting off access to roads, food and medical supplies have left humanitarian aid providers unable to reach the trapped populations of civilians not allowed to leave the cities. As previously seen in the provinces of Fua, Kefaya and Yarmouk, Eastern Ghouta has been the latest victim in the crisis with thousands of people being deprived of food and medical supplies, resulting in the deaths of many civilians, particularly infants and elderly.

In addition to the regime's siege, businesses are also accused of keeping prices high under the pretext of shortages. "The activists blame a four-year government siege and the greed of local businessmen, who hide food and medical products in orders to raise prices, for the malnutrition, mostly among children," Rami Abdurrahman of the Britain-based Syrian Observatory for Human Rights said. Food prices have rocketed since the forces loyal to Bashar Assad took control of several neighborhoods in May and destroyed tunnels that had been used to smuggle goods into the besieged area. This month, they closed Eastern Ghouta's main access checkpoint and imposed a hike in taxes imposed on traders.