Turkey and Iraq have summoned each other's ambassadors amid growing tensions between the two neighbours as they both fight Islamic State (IS).
Iraq's foreign ministry summoned Turkeys' ambassador to Baghdad to condemn allegedly "provocative" comments made by Turkish prime minister Binali Yildirim about the planned operation to dislodge IS militants from the northern city of Mosul.
Mr Yildrim told ruling party MPs in the Turkish parliament that the Iraqi operation could spark Shia-Sunni sectarian tensions if the majority Sunni region around Mosul were to be placed under Shia militia control after the offensive.
However, it is still unclear if the Shia militias, the core of the Iraqi paramilitary forces battling IS, will take an essential part in the Mosul operation.
Relations between Iraq and Turkey have become strained since late last year when Turkey sent unauthorised troops to the region of Bashiqa, north-east of Mosul, to train anti-IS fighters there.
Baghdad considers this a "blatant violation" of Iraq's sovereignty and has demanded Turkish withdrawal, a call Ankara has ignored.
Mr Yildrim's comments echoed those of Turkish president Recep Tayyip Erdogan days earlier during a parliamentary session in which Turkish MPs extended the mandate of Turkish forces in Syria and Iraq for one more year.
Mr Erdogan also expressed Turkey's willingness to join the imminent battle for Mosul.
In Iraq, the parliament adopted a resolution denouncing the extension of Turkish troops' presence and asking the government to consider them as "occupation forces".
Iraqi prime minister Haider al-Abadi later told reporters the presence of Turkish troops "is one of the challenges" ahead of the Mosul operation, warning that Ankara's insistence could lead to "regional warfare".
In Ankara, the Iraqi envoy was summoned for a protest over the Iraqi parliament resolution. The foreign ministry said Turkey has for years suffered from terror threats arising from instability in Iraq and had strongly supported Iraq's territorial integrity, stability and security.
Mosul, Iraq's second-largest city, located about 225 miles north-west of Baghdad, is the last remaining IS urban stronghold in the country. The government is now gearing up for a major offensive to retake Mosul from IS and has pledged to recapture the city this year.