A slim majority of 51.4 percent backed new congressional maps that could allow Democrats to flip as many as four House seats ahead of November's midterms.

Virginia backs new maps by narrow margin

Virginia voters have approved a redistricting measure that redraws the state's congressional boundaries, with 51.4 percent voting in favour and 48.5 percent against.

The new maps could allow Democrats to flip as many as four House seats, strengthening the party's prospects of taking control of the US House of Representatives in November.

Trump calls result 'rigged'

Former President Donald Trump called the vote "rigged" in remarks that followed the referendum result. Trump made the comments after the measure passed by the slim margin recorded in official results.

Part of a wider national fight

The Virginia vote is one episode in a broader national confrontation between Democrats and Republicans over congressional boundaries. Experts warn that an unprecedented series of tit-for-tat redistricting moves risks a surge in gerrymandering across multiple states, with analysts cautioning that ordinary voters may ultimately bear the cost of the escalating battle.

The contest had been considered tight in the lead-up to polling day, with a Democratic win always seen as the outcome most likely to translate into additional congressional seats.