Former CNN anchor Don Lemon, now an independent journalist, has been arrested for alleged involvement in an "coordinated attack" on a church during protests in Minnesota against an immigration crackdown, the US attorney general said Friday.

Pam Bondi, President Donald Trump's attorney general, said she had ordered the arrest of Lemon and three others, alleging they were involved in an "coordinated attack on Cities Church in St. Paul, Minnesota."

Lemon's lawyer said he was taken into custody in Los Angeles overnight, adding his work covering the protests "was no different to what he has always done."