A Philippine lawyer said he filed a complaint against President Rodrigo Duterte and senior officials at the International Criminal Court (ICC) on Monday, accusing them of crimes against humanity in a nationwide anti-drugs crackdown.

Attorney Jude Sabio said in the 77-page complaint that Duterte "repeatedly, unchangingly and continuously" committed crimes against humanity and that under him, killing drug suspects and other criminals has become "best practice."

Sabio is the lawyer for Edgar Matobato, a man who has testified in the Philippines Senate that he was part of a hit squad that operated on Duterte's orders.