WASHINGTON (Reuters) - The United States is concerned over reports that Shi'ite militia have set fire to homes as they advance on the Iraqi city of Tikrit, say U.S. officials, but they have not confirmed cases of abuse during the major offensive against Islamic State militants.
Iraqi security forces and mainly Shi'ite militia fought Sunni militants in Tikrit on Thursday, a day after they pushed into Saddam Hussein's home city in their biggest offensive yet against the militants.
U.S. officials said they were closely monitoring accounts from Tikrit, including video posted on social media, showing buildings being set ablaze. But attributing blame was tricky, they noted, pointing to accusations against both the Iran-backed militia and Islamic State fighters.
"What we know is that there are houses on fire," said one U.S. official, speaking on condition of anonymity.
The top U.S. military officer, General Martin Dempsey, told Congress this week he had "no doubt" the Iran-backed militia and Iraqi security forces would retake Tikrit. But he voiced concerns about treatment of Sunni Muslims there.
Islamic State fighters stormed into Tikrit last June during a lightning offensive that was halted just outside Baghdad. They have since used the complex of palaces built in Tikrit under Saddam, the executed former president, as their headquarters.
Another U.S. official urged caution but acknowledged "we are watching this very closely."
The United States says Baghdad did not seek aerial backup from the U.S.-led coalition in the Tikrit campaign. Instead, support on the ground has come from neighbouring Iran, Washington's long-time rival in the region. Tehran has sent an elite Revolutionary Guard commander to oversee part of the battle.
The situation on the ground was far from clear. Journalists have witnessed property burning. In some cases, militia fighters blamed retreating militants from Islamic State. In other cases, militia were suspected of targeting properties of alleged Islamic State sympathizers.
A U.S. security official said civilian casualties were believed to be very limited, since many local residents had long fled the city.
Prime Minister Haider al-Abadi has repeatedly told military commanders and militia leaders to respect civilians and maintain property in territory recaptured from Islamic State.
If Iraq's Shi'ite-led government retakes Tikrit, it would be the first city clawed back from the Sunni insurgents and would give it momentum in the next, pivotal stage of the campaign to recapture Mosul, the largest city in the north.
Reporting by Mark Hosenball, Phil Stewart and the Baghdad bureau; Editing by Dan Grebler