WASHINGTON -- Republican leaders unveiled a new health-care bill Thursday in their effort to deliver on seven years of promises to repeal and replace "Obamacare."

They immediately lost two key Senate votes, leaving none to spare as the party's own divisions put its top campaign pledge in serious jeopardy.

President Donald Trump declared a day earlier failure would make him "very angry," and he would blame Senate Majority Leader Mitch McConnell of Kentucky.

But talking with reporters aboard Air Force One en route to France, Trump also acknowledged the challenges lawmakers face.

"I'd say the only thing more difficult than peace between Israel and the Palestinians is health care," Trump said. "But I think we're going to have something that's really good and that people are going to like."

The reworked bill McConnell presented to fellow Republicans aims to win conservatives' support by letting insurers sell low-cost, skimpy policies. At the same time, he seeks to placate hesitant moderates by adding billions to combat opioid abuse and help consumers with skyrocketing insurance costs.

But it was not clear whether the Republican leader has achieved the delicate balance he needs after an embarrassing setback last month when he abruptly canceled a vote in the face of widespread opposition to a bill he crafted largely in secret.

Moderate Sen. Susan Collins of Maine told reporters she had informed McConnell she would be voting against beginning debate on the bill, citing in part cuts in the Medicaid health program for the poor and disabled.

Sen. Rand Paul of Kentucky, who repeatedly has complained McConnell's efforts don't amount to a full-blown repeal of Obamacare, also announced he was a "no."

That means McConnell cannot lose any other Republican senators. With Democrats unanimously opposed in a Senate split 52-48 in favor of the GOP, he needs 50 votes, with Vice President Mike Pence breaking the tie, to get past a procedural hurdle and begin debate on the bill.

The showdown vote is set for next week, though McConnell could cancel again if he's short of support. He and other GOP leaders are urging senators to vote in favor of opening debate, which would open the measure up to amendments.

And GOP leaders expressed optimism they are getting closer to a version that could pass the Senate.

"It's in the best shape it's been in so far," said Sen. Roy Blunt of Missouri. "Now that members actually have paper in their hand, they can look at what is likely to be very close to the final bill we'll be voting on and move forward."

McConnell said the 172-page legislation is the senators' opportunity to make good on years of promises.

Like legislation earlier passed by the House after struggles of its own, the Senate bill would get rid of Obamacare's mandates for individuals to buy insurance and for companies to offer it, repeal taxes and unwind the Medicaid expansion created by the Affordable Care Act. Analyses by the Congressional Budget Office have found the House bill and the earlier Senate version both would kick more than 20 million people off the insurance rolls over the next decade.

The new bill contains language demanded by conservative Sen. Ted Cruz of Texas letting insurers sell plans with minimal coverage, as long as they also sell policies that meet strict coverage requirements set by President Barack Obama's 2010 statute.

Moderate Republicans have objected that would make policies excessively costly for people with serious illnesses because healthy people would flock to the cheaper coverage.