President Barack Obama onstage at his farewell address in Chicago. AP Photo/Pablo Martinez Monsivais In a rare public statement, former President Barack Obama published a Facebook post on Thursday slamming the Senate Republicans' healthcare bill, the details of which were released on Thursday.

Echoing the criticism of top Democratic lawmakers, Obama argued that the intent of the bill, known as the Better Care Reconciliation Act, is not to improve healthcare, but to hand a "massive" tax break to wealthy individuals and businesses.

"The Senate bill, unveiled today, is not a health care bill," he wrote. "It’s a massive transfer of wealth from middle-class and poor families to the richest people in America."

Obama did not mince words in predicting that, if the bill is passed next week, it would harm vast numbers of Americans.

"Simply put, if there’s a chance you might get sick, get old, or start a family – this bill will do you harm," he wrote. "It would raise costs, reduce coverage, roll back protections, and ruin Medicaid as we know it," according to healthcare providers and non-partisan analysts.

He listed the ways in which the bill would reduce coverage.

"Those with private insurance will experience higher premiums and higher deductibles, with lower tax credits to help working families cover the costs, even as their plans might no longer cover pregnancy, mental health care, or expensive prescriptions," Obama wrote. "Discrimination based on pre-existing conditions could become the norm again. Millions of families will lose coverage entirely."

Obama also repeated a claim that he has made in the past: that he would support a Republican healthcare bill that improved upon his signature legislation, the Affordable Care Act.

"If Republicans could put together a plan that is demonstrably better than the improvements we made to our health care system, that covers as many people at less cost, I would gladly and publicly support it," Obama wrote.

He concluded that the healthcare debate is "something bigger than politics," and defines the nature of America.

"It’s about the character of our country – who we are, and who we aspire to be," he said.

The Better Care Reconciliation Act of would roll back much of the Affordable Care Act (better known as Obamacare), including various tax provisions, and scale back funding that goes toward health coverage for low-income Americans and tax credits for middle-income earners who purchase their own health insurance.

The plan would also provide funding designed to help stabilize the Obamacare insurance markets in the near term and funnel money through programs to cut off access to funding for abortion providers.

Moderates in the Senate are concerned about the bill's slashing of Medicaid spending. Obamacare's Medicaid expansion, which extended the program to those making 100% to 138% of the federal poverty limit, would be phased out over three years starting in 2020.

Senate Majority Leader Mitch McConnell is pushing for a vote on the bill by the end of next week.

Bob Bryan contributed to this report.