US President Barack Obama is a disappointment to the world, Iranian President Mahmoud Ahmadinejad said Wednesday night in an interview with the UK's Channel 4 News.Ahmadinejad mocked Obama's words in his Cairo speech, in which he said he was extending his hand to Iran. "Which hand did he extend? His right hand or left hand?" the Iranian president wryly asked. "He extended the sanctions against us.""He has failed to meet the expectations of the people in the US and the people of the world," Ahmadinejad added, once again rejecting America's year-end deadline for Teheran to respond to diplomatic outreach.Iran, said Ahmadinejad, has provided the US with a proposal which would enable "an opportunity for cooperation instead of confrontation."Earlier this week, Iran's president dug in his heels, saying that the US and its allies can set "as many deadlines as they want, we don't care," and that he was not moved by threats of sanctions. But the US is stressing that the upcoming deadline is serious and should be respected."Mr. Ahmadinejad may not recognize, for whatever reason, the deadline that looms, but that is a very real deadline for the international community. And I think all of those involved in the P5+1 would encourage Iran to take that deadline as seriously as it's being taken by us to live up to their responsibilities," said White House spokesman Robert Gibbs, referring to the negotiating group composed of the UN Security Council's permanent members and Germany.