Airstrikes hit the only road into rebel-held areas of Aleppo city on Sunday in the heaviest bombing since February, a rebel official and monitors said, jeopardizing access where around 300,000 Syrians live.
Russian warplanes carried out the attacks on the Castello road, which was still open but dangerous, the official and monitors said. Defense officials from Syria's government and its ally Russia could not immediately be reached for comment.
The Syrian Observatory for Human Rights group said the road was hit in a week of escalating airstrikes, with Sunday's attack the most intense yet.