Turkey has insisted that its forces cannot remain idle during the fight to drive so-called Islamic State militants from the Iraqi city of Mosul.
PM Binali Yildirim said it might be necessary to take action because Iraq and the US had not kept their promises.
He said both countries had allowed Shia militias and Kurdish separatists to take part in the operation.
Iraqi PM Haider al-Abadi on Saturday told the US that there was no need for Turkish forces as yet.
Fighting on the sixth day of the offensive on Saturday was reported to be intense, as the Iraqi military seized more ground.
Visiting US Defence Secretary Ash Carter has promised significant resources would be set aside for rebuilding Mosul once it had been recaptured from Islamic State (IS).
Correspondents say Mr Abadi’s refusal to countenance the prospect of Turkish involvement in the Mosul offensive could upset Turkish President Recip Tayyip Erdogan, who has warned of sectarian bloodshed if the Iraqi army relies on Shia militias to retake Mosul, which is mostly a Sunni Muslim city.
Mosul was once part of the Ottoman empire and Turkey sees the city as squarely within its zone of influence.
“I know that the Turks want to participate, we tell them thank you, this is something the Iraqis will handle,” Mr Abadi said after meeting Mr Carter in Baghdad on Saturday.
“If help is needed, we will ask for it from Turkey or from other regional countries,” he said.
Mr Carter meanwhile indicated his conditional backing for a possible Turkish role in the campaign, pointing out that there was an agreement in principle that could allow for eventual Turkish participation.
“Turkey… has an interest in the ultimate outcome in Mosul. Many other parties do as well. It’s a complicated city,” he said.
Meanwhile hundreds of people in Iraq are being treated for the effects of toxic gases after a sulphur plant was set alight in fighting with IS.
The US military says IS fighters set the plant on fire earlier this week, as they fled an advance by pro-government forces on their Mosul stronghold.
On Saturday, US soldiers at a base near Mosul donned protective masks as wind blew smoke towards them.
Reuters said another 1,000 people were being treated for breathing problems.
Advancing Iraqi forces on Saturday entered the town of Qaraqosh, about 30km (20 miles) south of Mosul, the IS capital.
Qaraqosh, Iraq’s largest Christian town before the war, is said to be largely empty but IS has laid landmines on the approaches to Mosul.
The militants have been attacking with suicide bombers elsewhere, driving vehicles laden with explosives at high speed towards government lines.
On Friday the militants attacked the city of Kirkuk, 170km (105 miles) south-east of Mosul, leaving at least 35 people dead and 120 wounded, according to medical sources.
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