Human Rights Watch is urging Iraqi forces and pro-government fighters to protect civilians as they press an offensive against the Islamic State group to reclaim the strategic city of Tikrit.
The group said Wednesday that is has documented multiple instances of those forces committing abuses after retaking other towns in Iraq, and stressed the need for all sides to make sure civilians are able to leave combat zones.
"The warring parties throughout Iraq need to protect civilians caught in the fighting and not commit looting or revenge killings," HRW's Deputy Middle East and North Africa Director Joe Stork said in a statement. "How the government fights this war will have an important impact on Iraq's future."
The Iraqi coalition launched an operation late Sunday with an estimated 30,000 fighters in the largest offensive to date to regain control of territory the government lost to the militants last year.
Islamic State fighters seized Tikrit in June, capturing the provincial capital and the birthplace of executed leader Saddam Hussein about 150 kilometers north of Baghdad.
Shi'ite and Kurdish militia members have joined Iraqi troops in the highly publicized military campaign, and neighboring Iran is also said to have a hand in rolling out the operation.
Major General Qasem Soleimani, who heads the elite Iranian special forces division known as the Quds Force, joined Iraqi Prime Minister Haider al-Abadi at the start of the offensive earlier this week.
But beyond the tactical support, the extent of Iran's involvement in the battle for Tikrit remains unclear.
A senior U.S. military official confirmed to VOA that Tehran is contributing to the Tikrit offensive.
A U.S.-led international coalition, which is responsible for daily air raids targeting the Islamic State group in Iraq and Syria, has been noticeably absent from the campaign. The military official said that as long as Iran is involved, the United States will stay out of the operation.
A victory in Tikrit would be a geographic stepping stone for Iraqi forces to approach Mosul, Iraq's second-largest city that serves as an IS stronghold and nerve center.