Seventeen US states to sue President Donald Trump to block his decision on Obamacare

A man fills out an information card during an Affordable Care Act outreach event. (File photo)

Seventeen US states as well as Washington D.C. will sue President Donald Trump to prevent him from revoking a key component of the Affordable Care Act, known as Obamacare.

The lawsuit was announced Friday to block the cutoff of critical Obamacare payments to health insurers that help millions of low-income people pay medical expenses.

The announcement came a day after Trump’s administration said it planned to end the payments next week.

"As far as the subsidies are concerned, I don't want to make the insurance companies rich," Trump told reporters at the White House. "They're making a fortune by getting that kind of money."

Announcing the lawsuit, New York Attorney Eric Schneiderman called Trump's decision "cruel," "breathtakingly reckless" and "unlawful."

"This is an effort to blow up the system," said Schneiderman (pictured below). "We will be in court to defend these subsidies and fight this decision with everything we've got."

Also, California Attorney General Xavier Becerra said, "In one week, the Trump Administration has re-opened the door to 'junk' health insurance plans and cut off access to contraception for millions of women.”

"Now they're refusing to comply with federal law in a way that will hike the cost of care for millions of Americans by withholding critical subsidies that make care more affordable."

California Attorney General Xavier Becerra (File photo)

Meanwhile, health insurance experts warned the move would financially harm middle-class Obamacare customers, saying this decision was being made at perhaps the worst possible time.

Former US Health and Human Services Department Secretary Kathleen Sebelius told CNBC that "this is really people's lives ... we're talking about your health, your kids' health and your parents' health."

"I think there's no question it will cause some insurers to rethink, potentially, being in the market at all, and it causes huge rate increases," Sebelius added.

During the last year election campaign, Trump promised to dismantle  Obamacare, former President Barack Obama's signature domestic policy achievement.

On Thursday, he signed an executive order he claimed would bring affordable health insurance to millions, taking his first concrete step in dismantling Obamacare.

The order, which tasks the administration with developing policies to increase health care quality and lower prices, is aimed at letting small businesses band together across the country to buy cheaper, less regulated health plans for their employees.