Aid trucks are waiting to deliver supplies to besieged Syrians amid a nationwide ceasefire that largely appears to be holding on its first full day, the UN says.
It is hoped that emergency aid deliveries will start on Wednesday.
Russian forces are monitoring the ceasefire along a key access road in northern Syria that leads to rebel-held eastern Aleppo, reports say.
Some 250,000 civilians are trapped there.
UN Special Envoy for Syria Staffan de Mistura said if the truce held, aid deliveries "should be taking place very, very soon".
He said the UN was waiting for the Syrian government to authorise deliveries and he hoped the people of Syria could look forward to "no bombs and more trucks".
Since the truce came into effect at sunset on Monday, accusations have been made against both rebels and government forces for sporadically violating it.
But there have been no reports of civilian deaths so far.
The Russian military claims US-backed groups have violated the ceasefire more than 20 times. including killing two government troops on the Castello road, which leads to rebel-held Aleppo.
The Russian foreign ministry called on the US "to deal with their clients".
Russia has deployed reconnaissance equipment in Aleppo to detect and suppress ceasefire violations.
The Syrian Observatory for Human Rights, a UK-based monitoring group, said pro-government forces had shelled two villages near Aleppo and an area near Damascus.
It earlier said it had seen reports of aerial bombardment of some villages in Hama province.