“Call me.”

That was the message early Friday morning from President Donald Trump to Democrats after he drew their ire late Thursday night for canceling health care subsidies they immediately said would drive up insurance premiums.

Trump took to Twitter even earlier than usual, 5:36 a.m., to boast about his decision, which Democrats and some health experts say could hurt low-income individuals and families the most.

Trump attempted to assign ownership of the health care system — and its many flaws — to the opposition party, writing “Democrats ObamaCare is imploding.” (He left off the apostrophe to grammatically assign ownership to the party.)

He called the 2010 law’s “cost-sharing reduction” payments a “massive subsidy” to the party’s “pet insurance companies.”

He then sent a message to Obama’s party: “Dems should call me to fix!”

The Democrats ObamaCare is imploding. Massive subsidy payments to their pet insurance companies has stopped. Dems should call me to fix!

— Donald J. Trump (@realDonaldTrump) October 13, 2017

In a tweet posted several hours later, Trump declared “ObamaCare is a broken mess.” He then seemed to describe the process that would be kicked off if Democrats do indeed make that call: “Piece by piece we will now begin the process of giving America the great HealthCare it deserves!”

ObamaCare is a broken mess. Piece by piece we will now begin the process of giving America the great HealthCare it deserves!

— Donald J. Trump (@realDonaldTrump) October 13, 2017

At issue is Trump’s decision to stop paying federal reimbursements to insurance companies under Barack Obama’s 2010 health law. The Trump administration for months had been paying the CSR payments, though the president had at times threatened to pull the plug.

He did just that on Thursday night.

“Based on guidance from the Department of Justice, the Department of Health and Human Services has concluded that there is no appropriation for cost-sharing reduction payments to insurance companies under Obamacare,” the White House said in a statement. “In light of this analysis, the Government cannot lawfully make the cost-sharing reduction payments.

“The bailout of insurance companies through these unlawful payments is yet another example of how the previous administration abused taxpayer dollars and skirted the law to prop up a broken system,” the White House added. “Congress needs to repeal and replace the disastrous Obamacare law.”

The reaction on Capitol Hill split, not surprisingly, along party lines.

Republicans, like Speaker Paul D. Ryan of Wisconsin, applauded the move. In a statement, he noted House Republicans won a court case challenging the legality of the Obama-era subsidies.

But Democrats slammed Trump’s move. It came hours after he signed an executive order intended to do away with a number of the 2010 law’s regulations in an attempt to make specific kinds of plans more available, according to White House officials.

“Not content to harm Americans with pre-existing conditions with his executive order earlier today, this President is now acting spitefully to raise premiums on millions of Americans and force a collapse of our health insurance marketplaces,” House Minority Whip Steny H. Hoyer, D-Md., said Thursday night.

“Unable to get his TrumpCare plan through Congress, the President is undermining bipartisan attempts to improve our health care system,” he said in a statement. “Ending cost-sharing reduction payments will make it harder for insurers to provide affordable coverage plans to consumers.”

This article was updated at 8:09 a.m.