Iraq's prime minister demanded on Saturday that Turkey withdraw troops it sent into the country to the northern city of Mosul.
About 150 Turkish soldiers were deployed to train Iraqi Kurdish forces near the town of Bashiqa Friday, Turkish military sources told the semi-official Anadolu Agency.
Prime Minister Haider al-Abadi called the move by Turkey a "serious breach of Iraqi sovereignty," in a statement released by his office.
"It has been confirmed to us that Turkish troops numbering around one regiment armoured with tanks and artillery entered the Iraqi territory, and specifically the province of Nineveh claim that they are training Iraqi groups without the request or authorization from the Iraqi federal authorities," the statement said.
"The Iraqi authorities call on Turkey to respect good neighborly relations and to withdraw immediately from the Iraqi territory," the prime minister said.
Anadolu Agency reported Turkish soldiers had been in the Mosul region for two-and-a-half years in order to train Iraqi Peshmerga forces.
The 150 Turkish troops sent Friday were to replace the previous unit.
Mosul has been under the control of ISIS since last year.
UPDATE
The former governor of Iraq's Nineveh province — Atheel al-Nujaif — said Tuesday that the recent arrival of Turkish troops had been "approved by Iraqi Prime Minister Haider al-Abadi and with the knowledge of Parliament Speaker Salim al-Jabouri", Turkey's semi-official news agency Anadolu reported.
On his Facebook page, al-Nujaifi said the arrival of Turkish forces "came at the request of the Iraqi prime minister during a meeting with his Turkish counterpart, Ahmet Davutoglu".
He said: "Al-Abadi asked for Turkish military assistance and Ankara responded by sending military supplies into Baghdad airport, like the Turkish troops sent to train our troops at Zlican Camp eight months earlier."
Al-Nujaifi served as governor of the province from 2009 until May this year.