TIKRIT — In the center of the Iraqi city of Tikrit, freshly sprayed graffiti on walls and shop fronts record the names of the groups that fought against Islamic State militants here.

While the Iraqi government insists that only Iraqi ground troops were involved, spray paint scrawled outside the city’s newly freed former presidential palace compound points to heavy Iranian influence on the ground and the possibility that some of Tehran's forces were present — even as planes from the U.S.-led coalition struck overhead.

“The Sepah of Khomeini defeated Daesh,” the graffiti read, but instead of Iraq’s native Arabic, it was written in the Farsi of neighboring Iran. Sepah, meaning “corps,” is a term used to refer to the Iranian Revolutionary Guard Corps set up by Iran's late Ayatollah Ruhollah Khomeini. Daesh is a term for the Islamic State derived from its Arabic acronym.

“Death to America” and “Death to Israel,” the Farsi graffiti continues, next to a large painting of the Islamic State flag.

The graffiti, however, also could have been the work of Iraqi militiamen interested in emphasizing an Iranian role.

In the distance, a hulking palace built by former president Saddam Hussein is partially obliterated by airstrikes — presumably launched from planes of the U.S.-led coalition, which were hitting targets in the city up until ground forces launched their final push on Monday night.

It’s a reminder that the battle for Tikrit has brought the United States and Iran into uncomfortably close quarters as they both try to prop up Iraq’s battle against militants from the Islamic State. A string of Shiite militias were present in the city Wednesday after entering in the wake of the bombing campaign, including Asaib Ahl al-Haq, the Badr Organization and Kitaeb Imam Ali.

While Iranian-backed militias have played down the U.S. role in the offensive and accusedthe  coalition of bombing their positions instead of those of the enemy, Washington also has been keen to stress the role of regular Iraqi security forces in an offensive where the militias played a major part.

Maj. Curtis Kellogg, a spokesman for U.S. Central Command, said in a written statement, "Based on our interaction with the Iraqi Government and reporting received through our Joint Operations Centers in Iraq, all pre-conditions for the execution of coalition airstrikes were met, to include we are not aware of any involvement by Iranian military advisors in the Tikrit offensive following the commencement of Coalition airstrikes."

Declaring victory in Tikrit on Tuesday, Iraqi Prime Minister Haider al-Abadi stressed that it was only Iraqi blood that was shed, though he said the fact that Iranian advisers were in the country was no secret. His spokesman wasn't available Wednesday night.

“We aren’t doing anything in secret that we are afraid to announce,” Abadi said. But the presence of small numbers of Iranian units has long been rumored, and a senior Iranian cleric close to the revolutionary guard said that combat troops from its elite Quds Force travel to Iraq “from time to time for specific operations.”