Most of the victims of the strikes, allegedly carried out by the Assad regime, were in the towns of Kafr Nabl and Maarat al Numan in the north-west of the country, activists said.
Air strikes have killed and injured dozens of people in the Syrian province of Idlib, bombings activists and civil defence officials blame on the Assad regime.
Most of the victims were in the towns of Kafr Nabl and Maarat al Numan, said the pro-opposition Syrian Observatory for Human Rights, based in London. Initial reports said at least 66 people had died. Later reports raised that figure to at least 73, with scores more injured.