The 400,000 civilian residents of the region have spent the past two weeks seeking shelter as Russia-backed government forces engage in one of the most intense sieges in the civil war's seven-year history.
A convoy of empty buses and 46 trucks carrying health and nutrition supplies and food for 27,500 people entered the eastern Ghouta town of Douma.
Syrian officials rejected a large amount of health supplies including trauma kits, surgical equipment, dialysis instruments and insulin — nearly emptying three trucks, according to a World Health Organization spokesperson.
The Syrian Observatory for Human Rights reported continued airstrikes at nearby front lines as the convoy drove on. A reporter for AFP news agency confirmed that airstrikes could still be heard as the aid was being unloaded.
Russia blamed the US for failing to reign in rebels during the designated ceasefire windows.
More than 1,500 people have been killed since Syrian government troops backed by Russia launched a ferocious attack on eastern Ghouta on February 18. Airstrikes have reduced much of the area near Damascus to ruins. According to the UN, there were an estimated 400,000 people trapped inside the besieged enclave without access to food and water when the offensive began.
'Hell on earth'
The town of Douma, with its 200,000 residents, is now the only remaining Ghouta pocket still under rebel control. The full recapture of eastern Ghouta would mark a significant victory for Syrian President Bashar Assad. Referring to the month-long assault on the enclave, UN Secretary General Antonio Guterres demanded "this hell on earth" be stopped immediately.
Reports of chemical attack
According to activists and doctors in the region, several people have suffered symptoms consistent with those triggered by a chlorine gas attack and had to be treated in hospital. French President Emmanuel Macron has warned the Syrian regime that the use of chemical weapons will result in French retaliation, but the Syrian government claims it has never used this kind of munition.
A man and child look at the remains of a missile in Douma, the largest in eastern Ghouta. More than 300,000 people have been killed since the conflict began in 2011, when the government cracked down on protesters who were calling for the release of political prisoners and for President Assad to step down.
'Rapid spread of malnutrition'
Activists say people in Douma have little food or water. Marten Mylius, the emergency relief coordinator for CARE in the Middle East, told DW that "after the tunnels were destroyed and the crossings closed, the price of basic foods skyrocketed. One kilo of rice now costs $4.50 (€3.66). A lot of people cannot afford that anymore. In other words, we are witnessing a rapid spread of malnutrition."
At the mercy of the regime
Aid access to eastern Ghouta is difficult because there is no direct route from neighboring countries. "In Idlib, for example...you can get in directly from the Turkish border. You can wait with supplies at the border and then bring in the convoy. It is much more difficult in eastern Ghouta," Mylius told DW.
Senior UN official Ali al-Za'tari, who is accompanying the convoy, told Reuters that he was "not really happy hearing the loud shelling that is around us" and that "we need to be assured that we will be able to deliver the humanitarian assistance under good conditions."
He said it would take hours to unload the trucks, which might not be able to return until after nightfall.
A spokeswoman for the International Committee of the Red Cross called the delivery a positive step but said more would need to be done. Ingy Sedky said the ICRC would require repeated and continuous access to eastern Ghouta.
Stalled attempts: For nearly three weeks, aid agencies have been trying to enter the besieged rebel-held enclave since the opening of daily "humanitarian corridors" but have been hampered by ongoing shelling and stringent time constraints.
Ongoing siege: Syrian government forces lost control of the semirural region in 2012 and recently launched a major offensive to regain control from jihadi groups. As of Monday the Syrian regime control a third of the rebel enclave, observers report. According to Syria's Central Military Media, troops advancing from the east were only 3 kilometers (1.8 miles) from meeting up with troops advancing from the west, which would cut the area in two.
War crimes: The UN has accused Syrian forces of perpetrating war crimes in its bloody push into eastern Ghouta, home to 400,000 people. On Monday the UN human rights body launched an investigation into attacks on civilians trapped in the area, and strongly condemned the bombardment of hospitals, the blockade of aid convoys and reports of chemical weapons use.