Russia's representative in international talks with Iran over its disputed nuclear programme, Sergei Ryabkov, met Tehran's top negotiator on a surprise visit on Wednesday, news agencies reported.

Ryabkov, who is also deputy foreign minister, met Saeed Jalili, who said Tehran "hopes for a swift return of the P5+1 countries to the negotiating table," the official news agency IRNA reported.

The recognition of Iran's right to enrich uranium "cannot be a precondition for talks but will be one of the topics of discussion," Ryabkov said, according to ISNA, another Iranian agency.

Ryabkov's visit came three days after he was quoted as telling Britain's Financial Times newspaper that Moscow would support direct talks between Iran and the United States on Tehran's disputed nuclear programme.

However, Iranian Foreign Minister Ali Akbar Salehi responded Monday by saying any "decision on comprehensive, bilateral political talks between the two countries... is up to the supreme leader," Ayatollah Ali Khamenei.

US President Barack Obama, whose re-election Iran welcomed with caution, said on Wednesday there was still a "window of time" to end the standoff and promised further diplomatic efforts.

"With respect to Iran, I very much want to see a diplomatic resolution to the problem," Obama told a White House press conference.

"I will try to make a push in the coming months to see if we can open up a dialogue between Iran and not just us, but the international community, to see if we can get this thing resolved."

Salehi, meanwhile, expressed hope that negotiations on its nuclear programme with the so-called P5+1 -- the UN Security Council's five permanent members plus Germany -- would resume soon.

The P5+1 has for years sought through negotiations with Iran to defuse an international crisis over Tehran's atomic ambitions, which the West believes has military aims despite repeated denials by the Islamic republic.

The last high-level talks, which all but failed, were held in Moscow in June.

According to Salehi, Jalili and EU foreign policy chief Catherine Ashton, who represents the world powers in the talks, are to hold a telephone conversation "to decide on a venue and date".

The UN atomic watchdog has said it will hold a new round of talks in Tehran on December 13.

The Security Council has imposed four sets of sanctions on the Islamic regime, which coupled with unilateral Western restrictions on its oil sector and banks, have begun to cause major problems for its economy.