(Senate Majority Leader Chuck Schumer slammed a Republican proposal to repeal Obamacare before passing a replacement healthcare bill on Tuesday.Alex Wong/Getty Images)

Senate Minority Leader Chuck Schumer, a New York Democrat, slammed a Republican proposal to repeal Obamacare before passing a replacement healthcare bill, calling the potential move "just as cruel, if not crueler."

President Donald Trump urged GOP lawmakers to repeal former President Barack Obama's signature legislation immediately after two more GOP lawmakers announced on Monday night that they would not support the Senate bill, effectively killing it.

"Republicans should just REPEAL failing ObamaCare now & work on a new Healthcare Plan that will start from a clean slate," Trump tweeted. "Dems will join in."

Schumer rejected Trump's call for a "repeal and delay," which Senate Majority Leader Mitch McConnell announced his support for on Monday night.

"Make no mistake about it: passing repeal without a replacement would be a disaster," Schumer said in a speech on the Senate floor on Tuesday morning. "Our healthcare system would implode, millions would lose coverage ... our healthcare system would be in such a deep hole that repair would be nearly impossible."

The minority leader used an analogy to illustrate his point.

"It's like if our healthcare system was a patient who came in and needed some medicine," Schumer said. "The Republicans propose surgery. The operation was a failure. Now the Republicans are proposing a second surgery that will surely kill the patient. Medicine is needed — bipartisan medicine — not a second surgery."

Schumer argued that Republicans should scrap the Better Care Reconciliation Act and work with Democrats to improve Obamacare.

"It's time to move on, it's time to start over," Schumer said. "Republicans should work with Democrats on a bill that lowers premiums, provides long-term stability to the markets, and improves our healthcare system."

He also rejected the GOP's claim that Democrats have been unwilling to work across the aisle on healthcare, arguing that Trump, along with Republican leaders in the House and Senate, began the policy debate by rejecting input from Democrats.

Schumer said his party is willing to work with the GOP as long as they "abandon cuts to Medicaid, abandon huge tax breaks for the wealthy, and agree to go through the regular order."

"The door is open right now, Republican leadership only needs to walk through it, as many Republican members are urging them," he said. "Republicans don't need to wreak havoc on our healthcare system first in order to get Democrats to the table — we're ready to sit down right now."