Former US President Donald Trump is accused of pressuring an employee to delete security footage at his Florida home, in new criminal charges related to his alleged mishandling of classified files.

The new indictment adds one count of wilful retention of defence information and two of obstruction, making 40 charges in total in this case.

Mr Trump, who is fighting multiple legal cases as he runs for president again, has denied any wrongdoing and called the prosecutor "deranged".