"We are not violating anything. We have stopped bombing anyone since the beginning of the ceasefire," he said. Russian bombing had continued but "not on the opposition positions", he said.
Russia hoped the cessation of hostilities - which excludes Daesh (ISIL) and Nusra Front fighters - would hold, he said, Reuters reported.
The US and Russia have agreed on a "cessation of hostilities" between the Syrian government and groups fighting it in a deal that excludes Daesh (ISIL) and the al-Nusra Front. The ceasefire went into effect across Syria on Saturday.