William Barr, the US attorney-general appointed by Donald Trump, on Monday authorised prosecutors to investigate possible instances of electoral fraud in this year’s presidential poll, a break from past practice that delayed such probes until after an election was settled.
The move, made in a memo issued to US attorneys across the country, came as Mr Trump continued to make unevidenced claims of fraud to dispute the victory of his Democratic rival, Joe Biden.
Mr Trump has refused to concede to Mr Biden, instead filing lawsuits that have generally been received sceptically by the courts. The Trump campaign on Monday filed a new case in Pennsylvania.