UPDATE 1-Obama says U.S. healthcare bills need more work

(Updates with background, details)

WASHINGTON, July 21 (Reuters) - President Barack Obama said in an interview aired on Tuesday that healthcare reform bills needed more work, but he was optimistic that the final legislation would drive down costs over the long-term.

Asked in an NBC "Today" interview whether he would sign any of the legislation being considered in Congress, Obama replied: "Right now, they're not where they need to be."

Obama has been pressing Congress to approve healthcare legislation, a centerpiece of his domestic agenda, before the August recess.

"I am deeply invested in getting this thing done," Obama said.

"This isn't Washington sport, this isn't about who's up and who's down. This is about solving an enormous problem for the American people," he said.

(Reporting by Tabassum Zakaria; Editing by Paul Simao)