The UN Security Council has called for a 30-day humanitarian truce in eastern Ghouta with the support of Syrian ally Russia after a flurry of last-minute negotiations.
The vote at the United Nations came on Saturday as warplanes pounded the last rebel enclave near Syria's capital for a seventh straight day while residents holed up in basements.
The Security Council approved the resolution to allow aid deliveries and medical evacuations.
However, the Syrian Observatory for Human Rights said warplanes struck eastern Ghouta on Saturday evening, minutes after the UN Security Council adopted the resolution.
The jets hit the town of Shifouniyeh in the rebel enclave, said the Britain-based monitoring group and two residents of the besieged suburbs near Damascus.
A surge of air strikes and shelling by the Syrian government and its allies has pounded eastern Ghouta since Sunday night, in one of the fiercest air-assaults of the seven-year war, residents, rescuers and the monitor say.
Rescuers said the bombing would not let up long enough for them to count the bodies during one of the bloodiest air assaults of the seven-year war, while
Medical charities have decried attacks on a dozen hospitals but the Damascus government and Russia say they only target militants. They have said they seek to stop mortar attacks injuring dozens in the capital, and have accused insurgents in Ghouta of holding people as human shields.