Aleppo: Several air strikes hit central and northern Syria on Sunday, a monitor said, but the first major ceasefire of the war appeared to be broadly intact on its second day.
Warplanes, believed to be either Syrian or Russian, bombed seven villages in the provinces of Aleppo and Hama, according to the Syrian Observatory for Human Rights.
Rami Abdel Rahman, the head of the Britain-based monitor, said one person was killed in Aleppo province.
It was unclear if the raids hit areas covered by the truce.
The agreement does not include territory held by the Islamic State jihadist group and Al-Qaeda-affiliated Al-Nusra Front, which together control more than half of Syrian land.
According to Abdel Rahman, only one of the villages, Kafr Hamra in Aleppo province, is controlled by Al-Nusra and the others are in the hands of non-jihadist rebels.
Elsewhere the situation remained mostly calm, according to AFP reporters.
In Aleppo, Syria's second city, the night passed without any sound of fighting or air raids, a correspondent said.
Residents took to the streets to do their shopping.
"There's something strange in this silence. We used to go to sleep and wake up with the sound of raids and artillery," said Abu Omar, 45, who runs a bakery in rebel-held east Aleppo.
"I'm happy but sad for regions that are not covered by the truce and whose inhabitants continue to suffer," he said.
Streets in Damascus were also bustling.
The temporary truce, brokered by Washington and Moscow, is seen as a crucial step towards ending a conflict that has claimed 270,000 lives and displaced more than half the population.
Russia, which has waged nearly five months of intense air strikes in support of Syrian President Bashar al-Assad, said Saturday it had halted bombing in all areas covered by the truce.
But it has vowed to keep striking IS, Al-Nusra and other "terrorist groups".
The US-led coalition fighting IS has also kept up its raids on the group, launching 12 strikes against jihadist positions in Syria on Saturday, it said in a statement.