New York based Human Rights Watch is calling for an investigation of an Iraqi airstrike that killed 31 civilians two weeks ago at a school housing displaced people near Tikrit.
The rights group says survivors report there were no militants or military equipment at the school.
Saturday, Iraq Prime Minister Haider al-Abadi ordered his forces to stop shelling populated areas held by militants in order to spare the lives of "innocent victims" as Iraq's military struggles to retake territory seized by the Islamic State group.
Al-Abadi accused the militants of using civilians as a human shield to stop the advance of Iraqi security forces.
U.S. Secretary of State John Kerry said the United States welcomes al-Abadi's order for his forces to stop shelling populated areas held by militants.
Speaking to the CBS News program Face the Nation, Kerry said "it is definitely something that the Sunni population in Iraq was very anxious to see happen."
Human Rights Watch special adviser Fred Abrahams said the Islamic State group "is incredibly brutal, but that is no excuse for what the Iraqi government is doing."
Abrahams called for Iraq's allies "to put pressure on Baghdad to stop this kind of violence."
Iraqi officials have not commented on the call for an investigation. But Human Rights Watch said the Iraqi government said the pilot had targeted a car driving near the school that was thought to be transporting fighters and explosives, causing an explosion that was "far larger than normal."
The army's tactics have long fueled anger among the country's Sunni minority, leading many to welcome the militants when they swept into Sunni-majority areas earlier this year.
The Shi'ite-led government has been under international pressure to reach out to Sunnis and Kurds to form a united front against the militants.