British police hunting for a Frenchman missing since Saturday's attack on London Bridge said they had found a body in the River Thames, potentially taking the death toll to eight.

British police said the formal identification of the body had not yet taken place but that the family of the missing Frenchman, 45-year-old Xavier Thomas, had been informed of the discovery.

France said earlier on Wednesday that two of its citizens had died when three men drove a van into revellers before going on a stabbing spree in central London on Saturday night. The foreign ministry said that a third French national was still missing and that four were seriously injured.

Le Parisien daily newspaper named the second Frenchman to die in the attack as 36-year-old Sebastian Belanger.