House Democrats delivered a fix-it-or-else ultimatum Wednesday to President Obama, giving his administration until Friday to find an affordable solution for the millions of Americans losing their health plans under ObamaCare -- or risk some Democrats backing a Republican solution.

The ultimatum from President Obama's own party is another sign of the unrest within the Democratic caucus about the cancellation notices. The end-of-the-week deadline is significant, because House Republicans are planning to call a vote Friday on a bill that would extend current policies for another year.

It's unclear whether Democrats would go so far as to support that bill if the administration does not offer a Plan B. But one senior Democratic source told Fox News that, at a closed meeting Wednesday, Democrats made clear to the administration that they need a proposed fix before Friday's vote.

The White House has vowed to come up with a solution, but so far has not provided much detail on what such a solution would entail. Press Secretary Jay Carney said Wednesday that the president will make an announcement on possible options "sooner rather than later."

One senior House Democrat characterized the meeting Wednesday as "heated." The source said the session consisted of "members telling the administration that they screwed it up and now we have to explain it to the public."

Another source said that it helps for the administration to hear frank talk "from their friends that they need to get back in front of the problem."

"No more excuses, just get it done," the source said.

The administration is facing a bipartisan wall of criticism about the plan cancellations. President Obama said repeatedly when he was selling the Affordable Care Act to the public that anyone who likes their plan can keep it.

What he didn't explain is that if any of those plans were modified after early 2010, they would be subject to ObamaCare requirements. Many plans have since been canceled because they did not meet the requirements -- customers are being offered new, and presumably better, plans in exchange, but some of them are considerably more expensive.

Bill Clinton fueled the debate on Tuesday when he said in an interview that Obama should find a way to "honor the commitment" to let people keep their current health plans.

On the heels of that statement, Sen. Dianne Feinstein, D-Calif., joined the call to reinstate those policies. Feinstein announced that she's co-sponsoring a bill by Sen. Mary Landrieu, D-La., that would reverse the cancellations by requiring insurance companies to continue to offer all current policies as of Dec. 31, 2013.

There are certainly still divisions among Democrats about the need to address the cancellations. Rep. Joseph Crowley, D-N.Y., said Wednesday that the House GOP bill coming up for a vote on Friday is merely an attempt to undermine the health law.

House Speaker John Boehner, though, said Wednesday that both chambers could soon move to pass bills addressing the cancellations.

"We're going to move a bill through the House this week. I'm optimistic that the Senate ... [is] starting to see some momentum over there to move a similar bill," he said. "This is not about politics. These are about real people in our districts that are being harmed by ObamaCare. It's time to fix this law."

Fox News' Chad Pergram contributed to this report.