 -- Two days after pointing his finger at Democrats for the failure of the GOP health care proposal, President Trump shifted the blame to conservative Republicans and said he is open to working with Democrats on health care reform.

On Twitter, Trump called out the conservative House Freedom Caucus, saying Democrats are "smiling" because the group's opposition to the Republican health care proposal "saved" Obamacare and Planned Parenthood.

"Democrats are smiling in D.C. that the Freedom Caucus, with the help of Club For Growth and Heritage, have saved Planned Parenthood & Ocare!" he tweeted Sunday morning, referring to conservative organizations the Club for Growth and the Heritage Foundation, which opposed the GOP health care bill.

Shortly after his tweet, his chief of staff, Reince Priebus, said the White House is open to working with Democrats on health care reform.

"Look, Obamacare, as we know, is imploding, and it is exploding and every other adjective you can provide. It's going south. It would be nice to get the Democrats on board," Priebus told Chris Wallace on "Fox News Sunday." "At the end of the day, I believe that it's time for the party to start governing. I think that's important. I think that Democrats can come to the table as well, and if you look at what the president said ... he said perhaps it's time for us to start talking to some moderate Democrats as well as come up with a bipartisan solution."

Trump's tweet about the Freedom Caucus marked a change from his reaction Friday after GOP leaders called off a vote in the House on the American Health Care Act because they didn't have enough support to pass the bill.

He said then he didn't feel betrayed by the conservative lawmakers who opposed the bill.

"They're friends of mine," he said of Freedom Caucus members. "I'm disappointed because we could have had [the bill pass]."

Instead, Trump on Friday laid the blame on Democrats. "We had no Democrat support," he said. "They weren't going to give us a single vote, so it's a very difficult thing to do."

The next morning, Trump tweeted to his followers, "Watch @JudgeJeanine on @FoxNews tonight at 9:00 P.M.," and on the show, host Jeanine Pirro opened with a call for House Speaker Paul Ryan to step down in the wake of the health care bill's failure.

But Ryan spokeswoman AshLee Strong told ABC News on Sunday that the relationship between the speaker and president is "stronger than ever right now."

"The two spoke again today," she said. "The president was clear his tweet [about Pirro's show] had nothing to do with the speaker. They are both eager to get back to work on the agenda."