US embassy spokesman Bob Callahan said on Monday the offer was made at a meeting on Saturday with the Association of Muslim Scholars (AMS), which has previously called on Iraqis to boycott the 30 January ballot.
But chances of Washington setting such a schedule for the withdrawal of roughly 150,000 troops are slim.
"That was their offer to us," said Callahan. "We have no intention to establish a timeline for withdrawal from Iraq at present. The Iraqi government agrees."
Members of the AMS were not immediately available for comment.
The talks suggest that with only three weeks before Iraqis go to the polls, efforts are under way to heal rifts over US attacks on Sunni areas and encourage the community once dominant under ousted leader Saddam Hussein to take part in the political process.
No timetable set
Callahan declined to name the US official who met the AMS officials to discuss Sunni participation in the election, but said it was not ambassador John Negroponte.
The mainly Sunni Muslim AMS has always said it would not field candidates for elections while foreign troops remained in Iraq.
But it went a step further in the build-up to a US assault on Falluja in November by calling on Iraqis to boycott the vote itself, dealing a blow to polls already threatened by relentless violence.