Iraqi Prime Minister Haidar al-Abadi has condemned Turkey's movement of troops into northern Iraq near Mosul to train Iraqi forces fighting the Islamic State (IS) group, and demanded their immediate withdrawal.
In a statement on December 5, Abadi said the entry of "around one armed battalion with a number of tanks and cannons" into the northern Nineveh Province was a violation of Iraq's sovereignty.
Iraq's Foreign Ministry described the entry of an estimated 150 Turkish soldiers and 25 tanks as "an incursion" and rejected any military operation that was not coordinated with the federal government in Baghdad, Reuters reported.
Turkish sources said the Turkish troops were deployed on December 4 as part of a "routine" exercise to provide training for Iraqi troops near Mosul, a city of more than 1 million people that IS forces captured in July 2014.
The Turkish sources maintained that Turkey already had troops in Iraq's autonomous Kurdistan region, and the United States and other countries involved in fighting IS there were aware it was moving some troops to the Mosul area.
U.S. officials in Washington said they were aware of Turkey's move, but it was not coordinated with the anti-IS coalition operating in northern Iraq.
The United States also moved this week to beef up its special forces fighting IS in northern Iraq, and got rebuffed by the Baghdad government despite attempts to work out the arrangement ahead of time.
Abadi appears to be under pressure from powerful Shi'ite Muslim groups that fought U.S. troops during the decade-long U.S. war in Iraq and now oppose any further deployment of U.S. or foreign troops in the country.
U.S. officials say they are still trying to work out an arrangement for their special forces in negotiations with Baghdad.
One key question is whether Baghdad will have any control over raids the United States conducts exclusively with Kurdish Peshmerga forces in northern Iraq, given that the Kurds often insist on acting independently from the Iraqi military.
Turkey has also cultivated a close relationship with the Kurdish government and by most accounts, Turkey's movement of troops into the Mosul area is only an expansion of its current presence in the autonomous Kurdish zone.
Turkey's close partnership with the Kurdish regional government comes despite its frequent battles with Kurdish rebel groups at home and in Iraq.
A senior Kurdish military officer based on the Bashiqa front line, north of Mosul, told Reuters that additional Turkish trainers had arrived at a camp in the area overnight escorted by a Turkish protection force.
The camp is used by a force called Hashid Watani (National Mobilization Units), which is made up of mainly Sunni Arab former Iraqi police and volunteers who fled Mosul after it was captured by IS.
The Watani force was formed by former Governor Athil al-Nujaifi, who is close to Turkey. There was already a small number of Turkish trainers there before this latest deployment
"Our soldiers are already in Iraq. A battalion of soldiers has gone there. Training was already being given in that region for the last two to three years. This is a part of that training," one senior Turkish official told Reuters.
Turkey had previously been criticized by its NATO allies for not doing enough to stem the rise of IS militants in Syria and Iraq. Turkey joined the U.S.-led coalition against IS only this year, in late July.
Before joining the coalition, Turkey had sought to stake out a more neutral stance toward IS. In June 2014, IS militants kidnapped 49 staff from Turkey's consulate in Mosul after seizing control of the city.
They were all released unharmed three months later after secret negotiations that reportedly resulted in the release of IS prisoners in Turkey in exchange for the embassy staff, AFP reported.