WASHINGTON - The US government on Thursday denied that its Secretary of State Hillary Clinton had asked Russia to warn Iran that the potential nuclear talks with world powers is its "last chance" for diplomacy.

"The secretary did not send a warning to the Iranians through Foreign Minister Lavrov," said State Department spokeswoman Victoria Nuland, in response to a report by Russian newspaper Kommersant.

The newspaper reported on Wednesday that Clinton has asked her Russian counterpart Sergei Lavrov, during their meeting at the United Nations headquarters in New York on Monday, to warn Iran that it has one "last chance" to reach a diplomatic solution in the expected nuclear talks with the six world powers over its disputed nuclear program. The Russian foreign ministry did not either confirm or deny the report.

Nuland noted that the conversation between the two chief diplomats in New York was centered around ensuring that the potential negotiations "bring substantive results" and "can't be used for stalling."

When asked if Clinton had used the words "last chance", Nuland said unequivocally: "She didn't use that adjective in her meeting. "

The P5+1 countries, namely the United States, China, Russia, France, Germany and Britain, have agreed to resume negotiations with Iran over its disputed nuclear program, with the date and venue for the talks to be decided.

The West has put in place unprecedentedly tough sanctions on Iran under the suspicion that the Islamic state is engaged in weapon-related nuclear activities. Both the United States and Israel have refused to rule out military option on Iran's nuclear issue.  

As a sign of increasing impatience, Israel has been clamoring for a preemptive strike on Iran's nuclear facilities before the country obtains the ability to make nuclear bombs. Last week, the country's Prime Minister Benjamin Netanyahu told US President Barack Obama in Washington that the Jewish state reserved the right to defend itself.

While insisting there is still time and space for a diplomatic solution on Iran, Obama warned on Wednesday that the window for diplomacy is "shrinking."