The US and Iraq have been discussing possible US airstrikes in support of a stalled Iraqi ground offensive against a dug-in Islamic State force in the northern city of Tikrit, US officials said on Wednesday.
The prospect of US airstrikes in Tikrit raises highly sensitive questions about participating in an Iraqi campaign that has been spearheaded by Iraqi Shiite militias trained and equipped by Iran, an avowed US adversary.
Iran has provided artillery and other weaponry for the Tikrit battle, and senior Iranian advisers have helped Iraq coordinate the offensive. Iraq pointedly did not request US air support when it launched the offensive in early March.
Recently, the offensive has lost momentum. Col. Steve Warren, a Pentagon spokesman, said Wednesday the Iraqi forces have encircled Tikrit but not yet made significant inroads into the heavily defended city limits.
"They are stalled," he said.
The US has hundreds of military advisers in Iraq helping its security forces plan operations against the Islamic State, which occupies large chunks of northern and western Iraq. But the US has said it is not coordinating any military actions with the Iranians.
Two US officials confirmed the talks about possible US airstrikes. They were not authorized to discuss the matter publicly on the record and so were granted anonymity.
Warren, the Pentagon spokesman, said Wednesday that at Baghdad's request the US began aerial surveillance over Tikrit in recent days and is sharing the collected intelligence with the Iraqi government.
The US-led air campaign, launched in August and joined by several European allies, has allowed Iraqi forces to halt the IS group's advance and claw back some of the territory it seized last summer.
But the growing Iranian presence on the ground has complicated the mission, with Washington refusing to work directly with a country it views as a regional menace.
The prominent role of the Shiite militias in the fight to retake Tikrit and other parts of Iraq's Sunni heartland has meanwhile raised concerns that the offensive could deepen the country's sectarian divide and drive Sunnis into the arms of the Islamic State group.
Warren would not discuss the prospect of US airstrikes in Tikrit nor comment on the possibility that U.S. aerial surveillance of the battlefield in recent days is aimed at identifying targets for potential US airstrikes.
A series of US airstrikes north of Tikrit, in the vicinity of Beiji, in recent weeks has had the indirect benefit of tying down Islamic State forces that might otherwise be operating in defense of Tikrit.
On Wednesday, for example, the US military said it had conducted five airstrikes Tuesday near Beiji, home of a major oil refinery that IS has sought to capture.
That bombing targeted IS combat units and destroyed what the US called an IS "fighting position," as well as an IS armored vehicle.