Supporters of Sen. Bernard Sanders in California have filed a federal lawsuit to extend voter registration for the state's June 7 primary, as the Democrats' nominating fight drags on to the bitter end.
The lawsuit claims election officials are not doing enough to publicize that the Democratic primary is open to independent voters, who have favored Mr. Sanders throughout his challenge to Hillary Clinton, the Los Angeles Times reported.
"Mistakes are being made," William Simpich, a civil rights attorney in Oakland who filed the lawsuit, told the newspaper. "There's mass confusion. This is a situation that really shouts out for some uniformity."
The lawsuit seeks to extend the March 31 registration deadline to June 7, the day of the primary.
The plaintiffs in the lawsuit include a group backing Mr. Sanders, according to the newspaper.
The battle between supporters for Mr. Sanders and the Democratic Party have grown increasingly hostile, as the Vermont senator charges that the party establishment has consistently worked to boost Mrs. Clinton toward the nomination.
Mrs. Clinton has declared herself the presumptive Democratic nominee and has a wide lead in the delegate hunt. But Mr. Sanders continues to win state primaries and has a strong campaign in California.
He has vowed to take his campaign to the party's July convention in Philadelphia.
The lawsuit's plaintiffs include two Bay Area voters and the American Independent Party. Also listed as a plaintiff is a group called the Voting Rights Defense Project, described as "an organization campaigning to heighten voter education and voter turnout for their candidate, Bernie Sanders," the Los Angeles Times reported.