Republican legislators in California announced Wednesday that they are sending a letter to the U.S. Department of Justice and to the U.S. Attorneys representing California, calling for a potential federal investigation into who is behind the proposed new congressional maps in California and how they were constructed.

California Democrats introduced a plan last week that could slash five Republican-held House seats in the liberal-leaning state while bolstering Democratic incumbents in other battleground districts.

The lawsuit comes as Newsom seeks a tit-for-tat expansion of California's House delegation to match a redistricting in Texas that would net Republicans five more seats.

California's Democratic Legislature is expected to counter Texas' mid-decade redraw of its congressional map with one of its own.

The national redistricting battle enters its next phase as California Democrats are scheduled to pass a new congressional map that creates five winnable seats for their party.