California Attorney General Xavier Becerra testifies in the U.S. Congress in September.

California, New York and 16 other states on Friday sued the Trump administration to force federal regulators to continue paying billions of dollars in cost-sharing insurance subsidies under the Affordable Care Act.

President Donald Trump announced Thursday he would end federal payments that help qualifying residents purchase insurance plans. More than one million Californians buy coverage through the Affordable Care Act’s health care exchanges.

The U.S. Department of Justice on Friday told the U.S. Court of Appeals for the D.C. Circuit, where the health care law’s cost-sharing subsidies are being challenged, that the federal government does not intend to make the next scheduled payment on Oct. 18.

[Jeff Sessions Memo, Reversing Obama Stance, Blesses End to ACA Subsidies]

California Attorney General Xavier Becerra on Friday called the president’s decision “sabotage, plain and simple.” A coalition of attorneys general—18 states and the District of Columbia—sought an order in the U.S. District Court for the Northern District of California to force the U.S. Department of Health and Human Services to make the Oct. 18 payment and all payments going forward.

“It’s long past time President Trump learned he doesn’t get to just pick and choose which laws he’ll follow or which bills he’ll pay, Becerra said.

Becerra this spring boosted his legal team’s health care expertise by hiring two attorneys familiar with the Affordable Care Act. Laura Stuber was oversight counsel at the U.S. Department of Health and Human Services where she coordinated the Obama administration’s defense of its health care policies in the Republican-controlled Congress. Melanie Fontes Rainer is the former chief of staff at the Centers for Medicare & Medicaid Services.

Becerra was joined on a media call by Massachusetts Attorney General Maura Healey, Connecticut Attorney General George Jepsen and Kentucky Attorney General Andy Beshear. New York Attorney General Eric Schneiderman joined the suit filed in California.

Becerra and Healey said the attorneys general will pursue claims that the subsidy payments are mandated by the Affordable Care Act and that the president violated the Administrative Procedures Act by unilaterally moving to stop them. Democratic state attorneys general have used the APA, with some success, to challenge Trump’s efforts to roll back Obama-administration regulations on energy efficiency standards, methane leaks on public lands and greenhouse-gas emissions standards.

Becerra, Schneiderman and other Democratic state attorneys general successfully intervened in the D.C. Circuit health care subsidies litigation this summer.

[DC Circuit Twice Says Democratic State AGs Can Fight Trump]

U.S. House Republicans sued in 2014 to stop the insurance subsidies. In 2016, U.S. District Judge Rosemary Collyer in Washington ruled for Republicans but stayed her order enjoining future cost-sharing payments until the Obama administration could appeal.

Becerra said it’s not clear yet what will happen to that case in light of Trump’s decision to end the cost-sharing subsidies. “We’re all staying tuned to find out where the federal Department of Justice is going on that,” he said.