Singapore, Nov.16 US President Barack Obama and his Russian counterpart Dmitry Medvedev have pledged to work together to prevent Iran's nuclear program from acquiring a dangerous hue and to renew a nuclear disarmament treaty that is set to expire in less than three weeks.

Medvedev has signalled that he is willing to join the United States in imposing sanctions on Iran, saying that if negotiations fail, "the other options remain on the table in order to move the process in a different direction."

"We're still not satisfied with the pace of advancement of the process," the Washington Times quoted Medvedev, as saying.

Obama emerged from a lengthy session with Medvedev at the posh Shangri-La hotel here to say he remains confident that the missile reduction treaty, which expires December 5, will be replaced by a new agreement by the end of this year.

Both leaders expressed impatience with Iran.

Obama called the proposal that has been offered to Iran "fair."

"Unfortunately, so far at least, Iran has been unable to say 'yes. We now are running out of time with respect to that approach," Obama said. (ANI)