Riverside County election officials on Saturday pressed Sheriff Chad Bianco to comply with a California Supreme Court order requiring the return of roughly 650,000 seized ballots after the court ruled the seizure unlawful. Bianco, a Republican, had signaled resistance to the directive.

The state's highest court on Friday ordered Bianco to relinquish the ballots to the Riverside County Registrar of Voters, rejecting his claim that the materials were needed for a fraud inquiry. The court found no legal basis for a sheriff to hold election records under state custody rules.

California Attorney General Rob Bonta and Secretary of State Shirley Weber, both Democrats, criticized the seizure as an attempt to interfere with lawful election administration. Bianco has aligned himself with President Donald Trump's push for federal reviews of state voter rolls.

The dispute intersects with a wider White House effort to accelerate reviews of at least 47 state voter rolls in a hunt for noncitizen voters. Voting-rights groups, including the American Civil Liberties Union of Southern California, warned that the Riverside case could set a precedent for local officials asserting control over ballots.

Bonta's office said it was prepared to seek contempt sanctions if Bianco failed to comply promptly. Continued defiance would escalate the confrontation between the county sheriff and California's judicial and executive branches.