President Donald Trump applied fresh pressure to Senate Republicans on Monday as they scramble to move forward with some form of a plan to repeal the Affordable Care Act this week.

In the White House surrounded by people he described as the victims of Obamacare, Trump firmly pushed GOP senators to support a highly unpopular overhaul of the American health-care system. Senate Republicans want to vote Tuesday on a motion to bring some version of a repeal bill up for debate, and the GOP appears to be in jeopardy of not having the support to do so amid party divisions.

"So far, Senate Republicans have not done their job in ending the Obamacare nightmare. They now have a chance, however, to hopefully, hopefully, fix what has been so badly broken for such a long time and that is through replacement of a horrible disaster known as Obamacare," Trump said.

The Senate is pushing for a vote Tuesday on a motion to proceed with a health-care bill, which would allow it to go up for debate and possible amendments. However, Republican leaders have not made clear which plan they want to move forward on once they proceed with the proposal.

At least two of the options face significant opposition from GOP senators. One, the repeal and replacement bill that Trump touted on Monday, stalled out amid skepticism from enough conservative and more moderate Republican senators to block it.

Both the repeal-and-replacement plan and repeal-first bill likely would not accomplish what Trump has said his health-care plan would do: increase coverage and broadly reduce costs for Americans, even those who are older or sicker, according to CBO estimates.

Another, a plan to repeal Obamacare and replace it during a two-year transition period, also lacks support, as it could create uncertainty and more instability in health-care markets. Several senators have said they do not want to repeal Obamacare without a replacement plan.

Trump, who highlighted cases of increased costs for consumers and insurers leaving individual state marketplaces under Obamacare, aimed to increase pressure on senators even before the vote on the motion to proceed.

"Any senator who votes against starting debate is telling America that you are fine with the Obamacare nightmare, which is what it is," he said.

Trump has ramped up his engagement with skeptical senators in recent days as the GOP tries to win over enough votes to repeal Obamacare and follow through on a campaign promise the party has made for most of the last decade. The GOP holds 52 Senate seats, and if Sen. John McCain, R-Ariz., remains out of the Senate fighting a brain tumor, it can only lose one party vote and still have the support to move forward with a plan.

Despite doubts that the GOP has the votes to pass the motion to proceed, Senate Majority Leader Mitch McConnell said Monday that the party will move forward with a vote on the motion to proceed Tuesday.

But it is unclear if last-minute efforts from both McConnell and Trump are enough to win over skeptical senators and pass the bill.

Trump tweet