"I think everybody in this room wants there to be a diplomatic solution to this problem. Having to take care of this problem militarily is in no one’s interest," Gates told a conference here on security in Asia.
"But it does put a premium on unanimity in the international community, and I would say especially in the UN Security Council, in terms of ratcheting up the pressure on the Iranians, not next year or the year after, right now," he said.
Gates said the general view of US intelligence is that Iran will be in a position to develop a nuclear device sometime between 2010 and 2015.
"There are those who believe that could happen much sooner, in late 2008 or 2009," he said. "The reality is that because of the way Iran has conducted its affairs, we really don’t know."
Iran denies it is working to acquire nuclear weapons, but has refused to halt a uranium enrichment program in defiance of UN sanctions.
Talks in Madrid between Iranian and European Union officials failed to break an impasse over the program Friday, prompting the US State Department to say it would press for new sanctions.
Gates said the sanctions should be severe enough to confront Iran with "serious trade-offs in terms of their economic wellbeing and their economic future for having nuclear weapons."