Trump tells Republican senators 'inaction is not an option' on health care

— -- After watching the Senate GOP's efforts to repeal and replace Obamacare flail and then flop, a seemingly frustrated President Donald Trump told Republican senators they "shouldn't leave town" until they "hammer" out health care legislation for him to sign.

Senate leadership is pushing for a vote on a measure that would repeal the Affordable Care Act and give lawmakers two years to work on a replacement. But today the president made clear he thinks Republicans should go the path of repeal and replace.

"We can repeal, but we should repeal and replace," Trump said to Senate Republicans, who traveled today from Capitol Hill to have lunch with him at the White House.

"We shouldn't leave town until this is complete and until we all go over to the Oval Office. I'll sign it, and we can celebrate for the American people," he said.

Trump seemed exasperated that Senate Republicans haven't been able to deliver on one of his top legislative goals.

"I've been here just six months. I'm ready to act," he said. "I have pen in hand. Believe me, I'm sitting in that office."

Senate Majority Leader Mitch McConnell has already delayed the Senate's August recess to continue working on health care. But late Monday night, he conceded that the effort to repeal and immediately provide replacement legislation for Obamacare "would be unsuccessful."

"People are hurting. Inaction is not an option. And frankly, I don't think we should leave town unless we have a health insurance plan, unless we can give our people great health care," Trump argued today.

Trump in a tweet Tuesday pointed the finger largely at Democrats but also acknowledged that "a few Republicans" were partly to blame, apparently referring to GOP Sens. Susan Collins, Rand Paul, Jerry Moran and Mike Lee, who announced their opposition to the health care bill.

Trump appeared to threaten — though jokingly and with a smile on his face — the Republican senators who defected.

"My friends, they really were and are. They might not be very much longer, but that's OK," he said to chuckles in the room.

He singled out Sen. Dean Heller of Nevada, seated next to him, who opposed the original version of the Senate health care plan before it was revised and who is undecided on the latest version of the bill.

"He wants to remain a senator, doesn't he?" Trump asked.

He added that any "senator who votes against starting debate is really telling America that you're fine with Obamacare."

A senior White House official told ABC News the lunch was entirely Trump's idea, since he wanted "one last shot" to persuade GOP senators to reconsider pushing Obamacare replacement legislation immediately.

Trump told reporters at the White House on Tuesday that he was "disappointed" with the failure of the Senate health care bill but said he doesn't "think it's dead."

He proposed that his party should let the health care system "fail" so that Democrats and Republicans can "come together and fix it and come up with a new plan."

Trump last hosted a group of GOP senators for lunch to talk health care on June 13 at the White House.

ABC News' Alexander Mallin contributed to this report.