The two biggest states to reject Obamacare's Medicaid expansion are accusing the administration of trying to force them into it.

Wading into an escalating skirmish between state and federal officials, Texas Gov. Greg Abbott said Monday he supports a lawsuit that his Florida counterpart, Gov. Rick Scott, announced last week. Scott filed suit against the administration over ending federal funds to pay hospitals for caring for the uninsured.

Federal officials have threatened to halt the funds unless Florida expands its Medicaid program under the Affordable Care Act, also known as Obamacare. A handful of states maintain funding pools to reimburse hospitals for care that would otherwise be uncompensated, but expanding Medicaid would reduce the need for such funds.

Both governors contend that the administration can't take steps aimed at forcing states to expand Medicaid, after the Supreme Court ruled in 2012 that states can opt out if they wish — as both Texas and Florida, who were plaintiffs in that case, have done.

"Florida's approach should be determined by Floridians, not coerced by federal bureaucrats," Abbott said in a statement.

But had Florida chosen to expand Medicaid to more low-income residents, that would have reduced the need for the federal dollars to pay for their uncompensated care, the Department of Health and Human Services noted in a recent letter to Florida warning the state's funding will likely not be renewed when it runs out June 30.

"Uncompensated care pool funding should not pay for costs that would be covered in Medicaid expansion," the agency wrote.

HHS officials also say the expiring funding should not come as a surprise to Florida, as they'd already outlined concerns with its uncompensated care program a year ago.

A similar battle could take place in Texas, which also has an uncompensated care program. But for now, officials said they've only notified other states of the Florida situation and will separately evaluate each state's uncompensated care program. Of the 21 states that have rejected Medicaid expansion, only some have such programs.

"We will also use these principles in considering similar proposals in other states, but discussions with each state will also take into account state specific circumstances," HHS spokesman Aaron Albright said.