After an encouraging start, Kurdish Peshmerga soldiers on the ground have begun protesting that the Iraqi military is too slow and weak to effectively liberate Mosul, and that their penchant for flying Shiite militia flags makes ethnic Kurdish and Arab Sunnis fear they may impose themselves once the Islamic State has been eradicated.

Speaking to the Wall Street Journal, Peshmerga General Sihad Barzani protested that his soldiers had effectively begun routing Islamic State jihadists out of the suburbs of Iraq’s second largest city, but that it appeared the Iraqi army could not work as effectively as the Peshmerga could. Baghdad has prohibited the Peshmerga from entering the Mosul city limits once the operation begins there.

“The Iraqi army hasn’t moved even a bit. The plan was us taking villages, and then the Iraqi army takes some of them. They didn’t,” Barzani, the brother of Kurdistan Regional Government President Masoud Barzani, protested. An Iraqi general told the Wall Street Journal his troops had not done anything because they were “waiting for the Peshmerga to finish.”

The first attempt to reclaim Mosul from the Islamic State, which conquered it in 2014 after the Iraqi soldiers protecting it fled, was aborted in March 2016 after Iraqi soldiers tasked with its liberation began fleeing the battlefield.

Barzani added that the Iraqi military had “a lot of cars with their slogans and flags,” meaning Shiite militias symbols, asking, “Is it the Iraqi army or is it the Iranian army?”

Iran supports a number of Shiite militias in Iraq that act independently of the anti-Islamic State coalition and of Baghdad. These militias have threatened to attack U.S. troops fighting in Iraq and stall their efforts against the Islamic State if they come into contact with Americans. About 5,000 U.S. special forces are currently embedded with the Peshmerga outside of Mosul.

Baghdad has assured concerned parties that the Shiite militias are not authorized to participate in the fight within Mosul, just like the Peshmerga, but the militias themselves have said they do not need “anyone’s permission” to enter the city.

On Wednesday, a Shiite militia coalition known as the Popular Mobilization Forces (PMF) asserted in a statement that they will enter the “center of Mosul,” where the Iraqi government has prohibited the Peshmerga from treading. “The PMF will be backing the security forces on the western front (..) along two axes. The first is Tal Afar and the second is to support the forces going into the center of Mosul,” a statement on the PMF website read, according to Reuters.

The Shiite militias have particularly incensed the government of Turkey, which has repeatedly insisted it has a right to participate in the liberation of Mosul to ensure that its Sunni population is not the target of ethnic cleansing operations.

“Mosul should be governed by the people of Mosul. Works to shape an international plan on Mosul’s status should begin now. Leaving the control of the city to groups from different regions would create worse problems,” Deputy Prime Minister Numan Kurtulmuş said on Wednesday.

“There could be some very bad results of a potential attack by the al-Hashd al-Shaabi [Shiite militias] on Sunnis in Mosul. Turkey will take every measure to prevent this from happening,” he added.

Iraqi Prime Minister Haider al-Abadi has accused Turkey of violating Iraq’s sovereignty and “invading” its territory by sending soldiers to cooperate in the struggle against the Islamic State. The Baghdad government is Shiite-controlled and largely distrusted by Sunni neighbors. His Turkish counterpart Recep Tayyip Erdogan has largely ignored Abadi, calling him “not on my level.”

American officials have expressed optimism that an Islamic State defeat in Mosul will not lead to sectarian violence.

“It’s well known that these villages in here where they advanced to yesterday—these were historically Kurdish villages. It would make sense that the Kurds would do the lion’s share of the work there,” Pentagon spokesman U.S. Navy Capt. Jeff Davis told the Wall Street Journal. “As they move closer to Mosul, that ethnic dynamic changes a bit, and I think you’ll see the Iraqi [security forces] begin to be more of the frontline troops.”