The US justice department is filing a lawsuit against California over new congressional maps that voters approved in an election last week.

The new maps favour Democrats and aim to cancel out gains made by Republicans through recently redrawn voting districts in Texas. Attorney General Pam Bondi accused California Governor Gavin Newsom of a "brazen" power grab using racially gerrymandered maps.

California voters overwhelmingly approved the redistricting bill known as Proposition 50, giving Democrats an advantage in five new congressional districts.

"These losers lost at the ballot box and soon they will also lose in court," a spokesperson for Newsom said in a statement to BBC News.

Bondi accused Newsom of attempting "to entrench one-party rule and silence millions of Californians" by pushing the new congressional district boundaries.

"Newsom should be concerned about keeping Californians safe and shutting down Antifa violence, not rigging his state for political gain," she said.

The justice department filed the complaint in a California federal court on Thursday, aiming to block the new maps.

Federal prosecutors accuse the Democratic governor and Secretary of State Shirley Weber of mandating "racially gerrymandered congressional districts" - a violation of the Equal Protection Clause of the 14th Amendment to the US Constitution.

Gerrymandering - the redrawing of congressional districts to give a party an electoral advantage - is legal in the US but unconstitutional if it is based on race.

The justice department cited "substantial evidence" that California legislature created a new map in which Latino demographics and racial considerations were predominant.

"Race cannot be used as a proxy to advance political interests, but that is precisely what the California General Assembly did with Prop 50," said Jesus A Osete, Principal Deputy Assistant Attorney General for Civil Rights in a statement.

"Californians were sold an illegal, racially gerrymandered map, but the U.S. Constitution prohibits its use in 2026 and beyond."

The maps are part of nationwide redistricting efforts initiated by President Donald Trump in order to tip the scales of the 2026 midterm elections in favour of his Republican Party to ensure their majority control of the US House of Representatives.

Newsom launched a campaign in August to suspend California's independently drawn maps in order to "fight fire with fire" as Republicans in Texas worked to change their maps at Trump's urging.

California's top lawyer, Attorney General Rob Bonta, defended Newsom and the ballot initiative, noting that several legal challenges had already been brought against Proposition 50 and none had prevailed.

"Californians spoke loud and clear" in the election, Bonta said in a statement. "They are sick and tired of Trump's lawlessness, of his lies, and of his inability to make life more affordable for all Americans. Their voices must be honored."

The California Republican Party and others filed a lawsuit last week challenging Proposition 50 and Bonta accused the federal justice department of "seeking to intervene" in that litigation. (BBC)

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