Pennsylvania Gov. Tom Wolf is slamming the GOP's plan to replace Obamacare as a "tax" on older Americans.

"You can call it the American whatever it is, but this is an age tax and it's a tax on people simply because we have aged," Wolf, a Democrat, said of the American Health Care Act, the plan put forward by the Republican-controlled Congress this week. 

That message was well-received by the small crowd at Center in the Park, a wellness center for older adults in the Germantown section of Philadelphia where Wolf called a press conference, along with local officials including state Sen. Sharif Street and City Council President Darrell Clarke. 

Citing an analysis by the Kaiser Family Foundation, Wolf said a 60-year-old Philadelphian with an income of $20,000 would receive $7,600 less in tax credits to buy insurance under the AHCA than under the Affordable Care Act. 

Echoing concerns expressed this week by AARP, the influential lobbying group for senior citizens, the Wolf administration argued the GOP plan would be especially onorous on older Americans who do not yet qualify for Medicare.

"That's those who are between the ages of 55 and 64 who under the proposed healthcare repeal plan can be charged up to five times more for the exact same healthcare coverage," said Secretary of Aging Teresa Osborn. "Simply not acceptable."

Under Obamacare, insurance companies are not allowed to charge older people more than three times as much as younger people. The GOP plan would expand this "rate band" to allow insurers to charge five times as much, which could slightly lower annual premiums for the average 24-year-old while raising annual premiums for a 64-year-old by more than $2,000, according to the RAND Corporation. 

The AHCA would also phase out federal funding for expanding the pool of people eligible for Medicaid, which extended coverage to more than 700,000 Pennsylvanians. 

Wolf admitted he does not know what his administration can do to ensure those people stay covered.

"This is the first Psalvo from Washington and frankly, we don't know what we'll be dealing with," said Wolf, claiming he has spoken with another governor -- a Republican who he declined to name, but said expressed similar concerns.

"While there's disagreement about what a state can do..., there's the general agreement that there's reason to be concerned," Wolf said.