BIRMINGHAM, Alabama (Reuters) - A "fairly large gap" exists between Alabama's Jefferson County and creditors over how to settle a $3.14 billion sewer bond debt ahead of a looming deadline, the county commission's president said on Tuesday.

Alabama's Jefferson County was due to make a decision last Thursday on whether to file what would be largest municipal bankruptcy in U.S. history.

But at the last moment, creditors who include JP Morgan Chase made a counter offer to settle the debt and the county agreed to extend the talks through this Friday.

"There's a fairly large gap between the county and the creditors, more than just dollars. There are terms and agreements (conditions)," said David Carrington after a meeting of the commission. He gave no details.

Carrington called a second executive session for this Thursday and the county has now scheduled a third such session for next Tuesday.

The county faces a twin fiscal crisis: a debt run up over bonds on its sewer system and a second one involving a shortfall of its general fund. Its combined debt stands at more than $4 billion.

(Reporting by Melinda Dickinson, Writing by Matthew Bigg, Editing by Kevin Gray and Chizu Nomiyama)