"It's wrong to attack Iran. It's wrong to start the war again. Iran is ready to negotiate on the nuclear file again," Foreign Minister Hakan Fidan told Qatar-based Al-Jazeera television.

"My advice has always been to our American friends: close the files one by one with the Iranians. Start with the nuclear issue and close it. Then move on to the others."

Fidan's comments came after a US naval force led by an aircraft carrier took up position in Middle Eastern waters, US Central Command said on Monday, without revealing its precise location.

Washington has not ruled out a new military intervention against Tehran over its harsh response this month to protests, which according to rights groups has left thousands dead.

Since Iran began its crackdown, accompanied by a nationwide internet blackout, US President Donald Trump has given mixed signals on intervention.

NATO member Turkey, which shares a 530-kilometre (330-mile) border with Iran, has often expressed opposition to military operations targeting the Islamic Republic.

Last week, President Recep Tayyip Erdogan described the unrest in Iran as a "new test" for Tehran, pledging Turkey would "stand against any initiative" that would drag the region into chaos.

He said he hoped diplomacy and dialogue would help Iran get through this "trap-filled period".

In a phone call on Wednesday, Fidan and Iran's Foreign Minister Abbas Araghchi evaluated "efforts to reduce tensions in light of recent developments in the region", a Turkish diplomatic source said.

Speaking to Al-Jazeera, Fidan said problems with Iran should be tackled individually.

"Do not treat them as a package. If you put everything together as one package, it will be very difficult for our Iranian friends to digest and truly process it," he said.

"In some cases, it may even seem humiliating for them. It would be hard to explain not only to themselves but also to their leadership."

The minister made similar comments Friday. He told Turkey's NTV he had visited Tehran late last year, urging them to "take steps" and he believed a nuclear agreement with Washington was "possible".

"A friend tells the bitter truth and I said what needed to be said," he said.

Fidan also urged Iran to build trust. "When I was in Iran two months ago, I was very frank with my Iranian friends. They need to build trust in the region," he told Al-Jazeera.

"They need to pay attention to how they are perceived by regional countries".