Iran says the United States should make it clear that it is ready to hold talks without conditions, and urged other countries in the Middle East to not put themselves in a "dangerous position."
Iranian Foreign Minister Ali Akbar Salehi made the comments Thursday during a visit to Turkey.
They come a day after the United States said it is open to resuming negotiations with Iran about its controversial nuclear program if Tehran is "serious" about discussing it openly.
State Department spokeswoman Victoria Nuland said Wednesday it is up to Iran to rejoin talks with the five permanent members of the U.N. Security Council and Germany, a group known as the P5+1. The parties last met a year ago.
An Iranian politician said Wednesday that U.S. President Barack Obama had sent a letter to Iran calling for direct talks. But the Obama administration did not confirm such contact.
White House spokesman Jay Carney said Wednesday that any communications that have or may have taken place are "the same in private as they have been in public," and that the path forward is through multi-party talks.
He said increasing pressure on Iran from the United States and "many international allies" is a direct result of Tehran's refusal to engage in "serious discussions" about its nuclear program.
Iran's Salehi said Wednesday any new negotiations likely would be held in Istanbul.
The U.S. State Department responded later that there have been no discussions about holding a new round of talks.
Meanwhile, U.S. Joints Chiefs of Staff Chairman Martin Dempsey is visiting Israel Thursday for talks with Defense Minister Ehud Barak, including U.S. and Israeli concerns that Iran is trying to develop nuclear weapons. Iran says its nuclear ambitions are peaceful.
The meeting comes a day after Barak said any decision about a preemptive Israeli attack on Iran's nuclear program is "very far off."
Israel and its key ally the United States have not ruled out using military force to stop Iran from building a nuclear bomb. But U.S. officials publicly have been urging Israel to avoid unilateral action and give more time for diplomatic pressure and sanctions on Iran to work.
Russian Foreign Minister Sergei Lavrov said Wednesday a military strike on Iran would be a "catastrophe" and would inflame tensions between Sunnis and Shi'ites in the region.
Lavrov also said sanctions imposed on Iran by the United States and European Union appear designed to hurt the Iranian economy rather than achieve the goal of nuclear non-proliferation. Russia has supported several rounds of U.N. Security Council sanctions on Iran in recent years but says it will not approve any more.
EU foreign ministers are set to finalize a proposed crude oil embargo on Iran to begin July 1 when they meet Monday in Brussels.
The EU also is likely to ban imports of Iranian petrochemical products and exports of key technology intended for Iran's petrochemical industry. An EU oil embargo would deprive Iran of vital foreign currency income.
Some information for this report was provided by AFP and Reuters.