* Obama says summit must not become 'political theater'
* Seeks to regain control of healthcare debate
* Criticizes insurers' huge profits
(updates with proposals to come out Monday)
By Ross Colvin and Jeff Mason
WASHINGTON, Feb 20 (Reuters) - The White House will unveil its latest healthcare reform proposals on Monday ahead of a bipartisan summit that President Barack Obama hopes will advance the stalled legislation, a senior administration official said on Saturday.
Obama urged Democrats and Republicans on Saturday to find common ground at a summit he will host on Thursday to help rejuvenate efforts to overhaul the $2.5 trillion U.S. healthcare system, one of his top domestic policy priorities.
The administration official said the White House would publish its updated proposals on Monday but declined to outline details.
The plan is expected to combine features of two Democratic bills passed by the Senate and House of Representatives, according to congressional aides and healthcare advocates.
They are expected to reflect common ground negotiated over the past several weeks by Democratic leaders in Congress.
Obama used his weekly radio and Internet address to take aim at health insurance companies, saying the "status quo is good for the insurance industry and bad for America."
Democrats are struggling to push healthcare legislation over the finish line in the face of sagging public support and solid Republican opposition bolstered by recent election victories in Massachusetts, Virginia and New Jersey.
"As bad as things are today, they'll only get worse if we fail to act. We'll see exploding premiums and out-of-pocket costs burn through more and more family budgets," Obama said.
Since the start of the year, Obama has sought to regain control of the healthcare debate, revive flagging enthusiasm for the overhaul among some Democratic lawmakers, and inject new momentum into the process.
Democrats have majorities in the Senate and House but are expected to lose seats to the Republicans in the mid-term congressional elections in November. The passage of a healthcare bill could boost Democrats' election hopes.
Obama said he had invited members of the Democratic and Republican parties to the healthcare summit to share ideas on how to bring down healthcare costs, which he has repeatedly warned threaten to cripple the U.S. economy.
"I hope they come in a spirit of good faith. I don't want to see this meeting turn into political theater, with each side simply reciting talking points and trying to score political points," he said.
"Instead, I ask members of both parties to seek common ground in an effort to solve a problem that's been with us for generations."
Republicans, who have accused Obama of trying to push through a government take-over of the healthcare system, have said they will attend but fear the White House is setting a trap, possibly preparing to blame them if the healthcare effort falters.
"Nearly one year ago, the president moderated a healthcare summit that kicked off a national debate that has led us to where we are today: a partisan bill devoid of support from the American people and a diminished faith in this government's capacity to listen. Let's not make the same mistake twice," Senate Republican leader Mitch McConnell said.
The administration, congressional Democrats and advocacy groups have also been turning up the rhetorical heat on health insurers that in recent weeks announced huge premium increases against the backdrop of sizable profits and growing numbers of uninsured people.
Obama echoed the criticism, saying the five largest insurers had made record profits of more than $12 billion even as millions of Americans lost their coverage.
additional reporting by Donna Smith; Editing by Paul Simao