The White House on Saturday denied that any deal had been reached for one-on-one nuclear talks with Iran, as the New York Times reported, and said it was still working on a "diplomatic solution."

The report and subsequent denial come at a key point in the U.S. presidential campaign, with incumbent Barack Obama set to face Republican rival Mitt Romney on Monday in their last of three debates -- this one focused on foreign policy.

Earlier, the New York Times -- citing unnamed officials in the Obama administration -- reported that the United States and Iran had agreed to one-on-one negotiations over Tehran's nuclear program.

The agreement was the result of secret talks between the two sides, the report said, adding that Iran had insisted that the negotiations not begin until after the U.S. presidential election on November 6.

But National Security Council spokesman Tommy Vietor quickly threw cold water on the Times report.

"It's not true that the United States and Iran have agreed to one-on-one talks or any meeting after the American elections," Vietor said in a statement.

Vietor said Washington would continue to work with global powers on a "diplomatic solution" to the nuclear standoff with Tehran. The U.S. "said from the outset that we would be prepared to meet bilaterally," he added.

Western powers accuse Tehran of seeking to develop a nuclear bomb, charges which Iranian leaders deny, saying their nuclear energy program is purely for civilian purposes.

Negotiations between the so-called P5+1 global powers -- Britain, China, France, Germany, Russia and the United States -- and Tehran over its nuclear program have stalled. Tough sanctions are aimed at forcing a breakthrough.

Russia said Thursday that a new round of talks between Iran's chief negotiator and six-nation representative Catherine Ashton, the European Union's foreign policy chief, could take place in November.

Romney has repeatedly accused Obama of having a weak stance on Iran. He has said he supports the same "red line" as Israel's Prime Minister Benjamin Netanyahu -- preventing Tehran from acquiring a nuclear weapons capacity.

But earlier this month he tamped down the rhetoric, saying any U.S. military intervention was "a long way" off.

Obama has consistently drawn the line on not allowing Iran to acquire a nuclear bomb -- a distinct difference from Netanyahu's line on achieving weapons "capacity."

Obama "has made clear that he will prevent Iran from getting a nuclear weapon, and we will do what we must to achieve that," Vietor said Saturday.

"It has always been our goal for sanctions to pressure Iran to come in line with its obligations. The onus is on the Iranians to do so, otherwise they will continue to face crippling sanctions and increased pressure," he added.

U.S. officials cited by the Times said the negotiations aimed at securing direct U.S.-Iran talks were conducted with people who report to supreme leader Ayatollah Ali Khamenei, but it was unclear if he had signed off on the deal.

U.S. officials also expressed concern that the Islamic republic could try to use the talks to stave off military action, buying time to complete elements of its nuclear program at hidden sites.

The Iranian side said it would like the talks to have a broader agenda including Syria and other issues that have bogged down relations between Washington and Tehran, the report said.

"We've always seen the nuclear issue as independent," one administration official told the Times on condition of anonymity. "We're not going to allow them to draw a linkage."

Israel's ambassador to the United States, Michael Oren, told the newspaper that the administration had not yet informed his country of any agreement on talks.

"We do not think Iran should be rewarded with direct talks," Oren said.

Before Vietor issued his statement, officials at the White House and the State Department had no comment when contacted by AFP about the Times report. (AFP)