WASHINGTON- President Barack Obama is completing work on a new strategy to counter opposition to a U.S. healthcare overhaul and outlining specific areas for compromise, a senior Obama official said on Wednesday.

Obama is considering outlining his new approach in a major speech as early as next week to coincide with the return of the U.S. Congress after lawmakers' August recess.

In the past month, Americans surveyed in polls have shown increasing concern about Obama's handling of healthcare and his popularity with voters has declined.

A CBS News poll on Tuesday said most Americans found healthcare proposals discussed in Congress confusing and said Obama had not clearly explained his plans to overhaul the system, his top legislative priority.

During the August recess, passions boiled over at some town hall meetings held by lawmakers in their home districts, with opponents and proponents of the healthcare changes engaging in shouting matches.

A senior Obama administration official, who spoke on condition of anonymity, said the healthcare debate is entering a new phase driven in part by negative comments from two Republican senators, Charles Grassley of Iowa and Mike Enzi of Wyoming, who had been part of a bipartisan group seeking a compromise.

The official said Obama considers now the time to pull together various strands from four bills that have been debated on Capitol Hill and other proposals. Basically all the cards are on the table, the official said.

The president is considering all of his options on how to advance the debate and get reform passed. This includes possibly laying out a more specific vision. No decisions have been made, though, the official said.

Obama has not dropped his desire for a government-run medical insurance option to compete with private insurers as a way to reduce healthcare costs for Americans. The so-called public option is favored by his liberal base but many lawmakers have doubts that such an option could gain passage in the Senate.

As a result, Obama and his aides have put less emphasis on the public option in recent weeks, stressing instead that he wants to increase choice and competition through the most acceptable means possible.

(Reporting by Steve Holland; Editing by Bill Trott)