UPDATE 1-US officials say Chrysler-Fiat deal still not certain

(Updates with fresh quote, paragraph four, background)

ST LOUIS, Missouri, April 29 (Reuters) - The Obama administration said on Wednesday U.S. auto-maker Chrysler LLC and Italy's Fiat (FIA.MI) needed to clear some hurdles if they were to complete an alliance before an April 30 deadline for a deal.

"I don't know if a deal is going to be finished or when a deal might be finished," White House spokesman Robert Gibbs told reporters aboard Air Force One on the way to Missouri, where President Barack Obama was due to hold a town hall meeting to mark his 100 days in office.

He did not say what obstacles lay in the way of a successful deal.

The U.S. Treasury Department has reached an agreement with Chrysler's largest creditors to cancel $6.9 billion of debt in exchange for $2 billion in cash.

"Hurdles still remain, but we remain optimistic and hopeful that something in the next many hours will get done that will provide a pathway for Chrysler's viability without continued government assistance," Gibbs said.

(Reporting by Caren Bohan, writing by Ross Colvin, editing by Jackie Frank)