“Unfortunately, so far at least, Iran appears to have been unable to say yes to what everyone acknowledges is a creative and constructive approach,” Obama said after talks with Medvedev on the sidelines of an Asia-Pacific summit in Singapore.

“We are running out of time with respect to that approach,” Reuters quoted Obama as saying

Medvedev also said, “We are prepared to work further” to ensure Iran”s nuclear program is only for peaceful purposes.

“In case we fail, the other options remain on the table, in order to move the process in a different direction,” AFP quoted the Russian leader as saying.

According to a draft deal drawn up by the IAEA, a large consignment of Iran’s enriched uranium would be shipped out of the country for processing into fuel rods with a purity of 20 percent for the Tehran reactor. However, many Iranian officials, including parliamentarians, believe that that Iran should buy the fuel for the reactor without sending its own low-enriched uranium (LEU) abroad.

Iran has called for more talks.

A senior adviser to Iran’s President Mahmoud Ahmadinejad said no official response to the proposal had been announced.

“We are waiting to see how much sincerity the Western countries have in their pledges,” said Mojtaba Samareh-Hashemi.

White House spokesman Robert Gibbs said an end-of-year deadline for Iran remained.

Russian officials such as foreign minister Sergei Lavrov have said Washington was trying to push Moscow into a position of publicly threatening the imposition of sanctions soon if Iran did not play ball.

Iran says it is enriching uranium only for power plant fuel, not for nuclear warheads.

The IAEA is consulting on possible compromises to save the deal, including Iran placing its LEU under escrow in a friendly third country, like Turkey, pending delivery of reactor fuel. Iran and Turkey discussed the idea in talks this month.

Iran’s presidential adviser Samareh-Hashemi said regarding Turkey’s role: “Turkey is also on the cards but they have not come to a firm agreement or decision to act accordingly.”