Philippine presidential candidate Rodrigo Duterte gestures during a labor day campaign rally on May 1, 2016 in Manila, Philippines.

Philippine President Rodrigo Duterte on Monday hit out at what he called "bullshit" Western threats to seek his indictment by the International Criminal Court (ICC) over his role in a bloody crackdown on drugs.

Police figures show Duterte's campaign has killed more than 2,500 people since he took office on June 30, about three-quarters in police counter-narcotics operations, and the rest believed to be the victims of vigilantes or drug lords eliminating rivals or silencing those who could implicate them.