Foreign Ministry spokesman Selcuk Unal said Turkey would evaluate the content of the sanctions expected to be announced by the United States but it "does not feel it is bound by any other sanctions."

On Thursday, Japan pledged to buy less Iranian oil, boosting the US campaign a day after China reacted coolly to the idea.

The sanctions aim to halt what Western governments say is Iran's effort to develop nuclear weapons. The sanctions, targeting the oil industry, would bar financial institutions from the US market if they do business with Iran's central bank.

Unal's statement came as Iranian Parliament Speaker Ali Larijani held talks on Tehran's nuclear program with Turkish Foreign Minister Ahmet Davutoglu, a Turkish diplomatic source said.

The source said the fragile situation in Iraq, locked in a political standoff that has raised sectarian tensions after the withdrawal of US troops, also featured during a breakfast meeting.

"Of course Iran's nuclear program was discussed," the source said, speaking on condition of anonymity.

Larijani is to meet with Turkish Parliament Speaker Cemil Cicek, Prime Minister Recep Tayyip Erdogan and President Abdullah Gul during his visit.

The European Union is also expected to announce further sanctions of its own, including an oil embargo, at the end of this month.