JUNEAU, Alaska (AP) — Officials in Alaska on Friday were evaluating the impact of a Trump administration decision to stop payments to insurers that help lower copays and deductibles for people with modest incomes under an Obama-era health care law.

The White House said the government can't legally continue paying the so-called cost-sharing subsidies because they lack a formal authorization by Congress.

Earlier this year, Premera Blue Cross Blue Shield submitted rate filings with the state of Alaska for two scenarios: continued receipt of the payments and discontinuation of the payments. Premera is the lone provider of individual health policies in Alaska.

Premera projected an average rate decrease of 21.6 percent in 2018, assuming it would not receive the payments. The anticipated rate decrease if the payments continued was 26.5 percent.

State Division of Insurance Director Lori Wing-Heier said by email that the state still projects an average decrease of about 21 percent.

Premera, in making its rate filings, attributed the requested drop to factors including the payment of high-cost claims through a state program and a sharp reduction in the use of medical services by customers. It called the rate decrease encouraging but cautioned against drawing any conclusions about a small Alaska market that it said remained volatile.

Premera spokeswoman Melanie Coon said Friday that as provisions are removed from the Affordable Care Act, it could have a destabilization effect.

"If there's no incentive for people to purchase and maintain their coverage, then you're going to have fewer people," she said. "That's going to affect the market's ability to be stable because you need as many people as possible to take on the costs of those high claims."

Cori Mills, a spokeswoman for the state Department of Law, said the department was processing the Trump administration's decision.

"At this point, we have not received a specific request from another state to join in a lawsuit, but it is still early," she wrote in an email.

Critics worry the decision will create greater uncertainty in what is already a small marketplace in a high-cost, rural state.

"They're essentially accelerating the collapse of health care, in my opinion, and by accelerating it like that, it's effectively making the system worse," said Andre Horton, director of the advocacy coalition Protect Our Care Alaska. He cited concern with the latest decision and cuts in funds for enrollment outreach. The new open enrollment period starts next month.