Former US President Donald Trump has been criminally charged with plotting to overturn his 2020 election defeat.

He is accused of four counts, including conspiracy to defraud the US, tampering with a witness and conspiracy against the rights of citizens.

The indictment caps an inquiry into events surrounding the January 6, 2021 riot at the US Capitol. 

Mr Trump, who is again running for president, denies wrongdoing, and on social media called the case “ridiculous”.

He is already charged in two other cases: with mishandling classified files, and falsifying business records to cover up a hush-money payment to a porn star.