The government of the United States announced Thursday that it has decided to end the cost-sharing subsidies for health insurance companies that were covered by the current health law, a setback for health insurance markets.

The subsidies are used to fund the expenses of people wit low incomes.

"The government cannot lawfully make the cost-sharing reduction payments," the White House said.

This measure followed the executive order signed Thursday by US President Donald Trump to start dismantling his predecessor Barack Obama's health law, after the Republicans' successive failures to approve a new reform in Congress.

Although one of Trump's campaign promises was to repeal and replace Obamacare, the Republicans have so far been unable to pass a new health care bill in Congress despite their control of both houses.

According to the White House press secretary, "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 subsidies, estimated at $7 billion this year and paid in monthly installments, can be halted almost immediately because Congress has not approved the program funding.

Experts predict that this fund suspension will be a hard blow to the already fragile Obamacare health insurance markets, with fears or rising premiums and insurers withdrawing from the market.

Nancy Pelosi and Chuck Schumer, the Democratic Leaders of the House of Representatives and of the Senate respectively, condemned Trump's actions.

"Sadly, instead of working to lower health costs for Americans, it seems President Trump will single-handedly hike Americans' health premiums," they said in a joint statement.

"It is a spiteful act of vast, pointless sabotage leveled at working families and the middle class in every corner of America. Make no mistake about it," they added.

The Democrats, who have repeatedly offered to negotiate a bipartisan reform, insisted that the president's decision came in the wake of his inability to repeal and replace the current health care system he had promised during the election campaign, so he aimed to crush it from within.