President Donald Trump’s decision to end a provision of the Affordable Care Act that lowered out-of-pocket medical costs brought swift reaction Friday from the states, as health officials and consumers said they feared the action could chase millions of Americans away from coverage.

Attorneys general in nearly 20 states said they planned to sue the Trump administration to keep the money flowing, contending that the president is not following a legal requirement to pay the subsidies.

“This is a president who seems set on enacting reckless, unlawful campaign promises no matter the harm to families in America,” Massachusetts Attorney General Maura Healey said during a conference call.

At issue is a federal subsidy for deductibles and co-pays that helps lower costs for consumers with modest incomes. The Trump administration and many Republicans say the government cannot legally continue to make the so-called cost-sharing payments.

State officials say ending the subsidies will make insurance premiums skyrocket, forcing some consumers to give up having coverage at all.

“Scared, anxious and worried,” said Carmen Parra, a 64-year-old Miami nanny when asked for her reaction to Trump’s decision.

The federal cost-sharing payments cover nearly 95 percent of her deductible and co-pay costs. For example, she pays just $2 each for blood pressure and asthma medications, and an urgent care visit for one asthma attack costs just $15.

Without the subsidies, Parra said she could be forced to go without insurance. Her state has led the country in insurance enrollment under the Affordable Care Act, nearly 1.7 million consumers signing up for coverage. About three-fourths of them receive federal subsidies of some kind.

“Please consider the people who need this assistance so they can live. Our lives depend on it,” Parra said in Spanish through a translator.

Trump’s announcement Thursday came weeks after the failure of the latest Republican attempt to repeal former President Barack Obama’s Affordable Care Act. It’s less than three weeks before the start of open enrollment, when many Americans who do not have health insurance through their employers can start picking their plans.

The payments to insurance companies are a major piece of Obama’s overhaul, which extended coverage to low- and moderate-income people in multiple ways. More than 6 million people benefit from the cost-sharing subsidies, which cost the federal government about $7 billion a year. That cost is expected to more than double within a decade.

Cost-sharing is aimed specifically at people who buy coverage on government run exchanges and make between 100 and 250 percent of the federal poverty level — between about $12,000 and $30,000 for single people.