The group said on Tuesday that ground units loyal to President Bashar al-Assad had taken control of more than 40 percent of the district.
Earlier in the day, Syria's official SANA news agency said buses have been waiting near the safe corridor to transport the people leaving Eastern Ghouta to a housing center set up by the government, but no civilians have so far managed to get out.
All U.N. vehicles and OCHA staff should be allowed to enter the biggest eastern Ghouta town of Douma on Thursday with the medical supplies that were removed on Monday, and without their vehicles being subjected to inspections, he said.
After six and a half years collecting evidence, commission members said on Tuesday that they planned to work vigorously on behalf of the victims but emphasized "there can be no trade-off between justice for the victims and a viable political solution" to the conflict.
The Assad regime, backed by Russian Federation, claims that it is only targeting "members of banned terrorist groups who are unprotected by the truce", as Reuters puts it.
Earlier on Wednesday, Reuters News Agency reported that a military spokesperson for an unnamed rebel group said that they will not accept a negotiation brought forward by Russian Federation. A March 7 Kremlin statement about the gathering did not specify the exact date or where the meeting would take place.More news: Tripura debacle revives debate in CPM on anti-BJP alliances
It comes amid a crushing Syrian government military offensive on eastern Ghouta, home to about 400,000 people. Raids on Tuesday reportedly killed 24 people.
The Russian mission to the United Nations in Geneva did not immediately respond to the findings.
It came as it emerged that children inside eastern Ghouta are surviving on a single meal a day of boiled wheat mixed with sugar.
The investigators also spoke of allegations of chemical weapons use in the enclave, saying they had "reasonable grounds to believe that government forces used chemical weapons" in an attack on Harasta on November 18. It says the rebels are also free to leave the enclave with their weapons and families unhindered.
A humanitarian convoy was able to reach the besieged eastern suburbs of Damascus on Monday, but aid workers were forced to halt delivery of supplies due to security concerns.
Aksoy said the camps would host a total of 170,000 people.
"You have a horrific human impact of the bombing ... hundreds of civilians killed in the last 10 days, thousands injured". The goal of the operation is clear Turkey's Syrian border from the terrorist threat.