The rights organization, in a 38-page report, states that Syrian forces killed at least 95 citizens in late March and early April. Former U.N. Secretary-General Kofi Annan helped broker a cease-fire that was to go into effect April 10.
"While diplomats argued over details of Annan's peace plan, Syrian tanks and helicopters attacked one town in Idlib after another," Anna Neistat, associate director for program and emergencies at Human Rights Watch, said in a statement from New York.
Human Rights Watch said it based its report on field investigations. It said government forces summarily executed 35 civilians during their assaults.
"It was as if the Syrian government forces used every minute before the cease-fire to cause harm," said Neistat.
The Syrian government maintains it is dealing with armed domestic terrorists inside the country. The official Syrian Arab News Agency reports Wednesday that President Bashar Assad granted "a general amnesty for all penalties provided in some articles of the military service law and military penal code."
A small team of U.N. observers is in Syria to monitor the cease-fire.