President Trump said Wednesday he does not support a bipartisan plan to stabilize Obamacare, saying the deal would bail out insurance companies "who have made a fortune" under Obamacare.

"I am supportive of Lamar as a person & also of the process, but I can never support bailing out ins co's who have made a fortune w/ O'Care," Trump tweeted Wednesday morning, referencing Sen. Lamar Alexander, R-Tenn.

I am supportive of Lamar as a person & also of the process, but I can never support bailing out ins co's who have made a fortune w/ O'Care. — Donald J. Trump (@realDonaldTrump) October 18, 2017

Alexander and Sen. Patty Murray, D-Wash., the top two members of the Senate Health, Education, Labor and Pensions Committee, announced Tuesday a deal to fund insurer payments known as cost-sharing reduction subsidies for two years.

Related: Key questions about the Senate's Obamacare subsidy deal

Trump ended the cost-sharing reduction subsidies last week, but he signaled support for the deal from Alexander and Murray during a press conference in the Rose Garden on Tuesday.

"It is a short-term solution, so that we don't have this very dangerous little period — including dangerous periods for insurance companies," the president said. "For a period of one year, two years, we will have a very good solution."

Trump also told reporters he was aware of the negotiations between Alexander and Murray.

"Lamar has been working very, very hard with the Democratic — his colleagues on the other side, and Patty Murray is one of them, in particular," the president said. "And they're coming up and they're very close to a short-term solution. The solution will be for about a year or two years, and it'll get us over this intermediate hump."

But hours later, in a speech before conservative donors and policy makers at an event for The Heritage Foundation, Trump appeared to walk back his initial support for the bipartisan deal.

"I'm pleased the Democrats have finally responded to my call for them to take responsibility for their Obamacare disaster and work with Republicans to provide much-needed relief to the American people," Trump said. "While I commend the bipartisan work done by Senators Alexander and Murray, and I do commend it, I continue to believe Congress must find a solution to the Obamacare mess instead of providing bailouts to insurance companies."

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Alexander said he spoke with Trump on Wednesday morning about the bipartisan deal, and told attendees of an Axios event in Washington the president "intends to review it carefully and see if he wants to add to it."

In addition to funding the cost-sharing reduction subsidies for two years, the deal from Alexander and Murray would also allow insurance companies to sell "copper plans" to consumers who are older than 30.

States could also apply for waivers to adjust Obamacare's rules, and the process for applying for and receiving those waivers from federal officials would be quicker.

The "bailout" label has been attached by several conservatives skeptical of giving billions of dollars to insurers. In 2016, the federal goverment gave out $7 billion in cost-sharing subsidies to insurers.

The subsidies go to insurers to reimburse them for lowering copays and deductibles for low-income Obamacare customers. Insurers are required to lower the out-of-pocket costs for low-income customers so experts predict they will raise premiums for everyone on Obamacare's exchanges on the individual market, which is used by people that don't get insurance through a job or the government, to recoup the costs.

The nonpartisan Kaiser Family Foundation estimates that premiums could go up nearly 20 percent in 2018.

Robert King contributed to this story.