Syria has granted permission for aid workers to enter four hard-hit provinces, the United Nations has said.
The UN Office for the Co-ordination of Humanitarian Affairs said the Syrian government agreed in writing to allow in aid workers and convoys with supplies to Daraa, Deir el-Zour, Homs and Idlib.
Spokesman John Ging told reporters that Damascus and an ambassador in Geneva pledged to grant visas and clear up the other bureaucratic hurdles that have blocked help from being delivered by nine UN agencies and seven international non-governmental organisations.
Mr Ging said that "whether this is a breakthrough or not will be measured in the coming weeks" by whether Syria makes good on its promise.
He said he hopes to have workers and supplies entering within days, not weeks.
The move comes after rebel forces killed dozens of Syrian soldiers in the past few days.
The Britain-based Syrian Observatory for Human Rights, which has a network of sources on the ground, said 113 soldiers had been killed in clashes with rebel forces across the country since Friday.
The figure was impossible to confirm independently, but the Syrian government confirmed nearly 80 soldiers had been killed over the past three days.
Mr Ging said at least a million Syrians are in urgent need of some form of humanitarian aid, including people injured during fighting, and families who have lost jobs or homes.
More than 78,000 Syrian refugees are also being helped in Iraq, Jordan, Lebanon and Turkey, the UN refugee agency said.