"It is apparent that the ICC is being utilised as a political tool against the Philippines," Duterte said. He slammed "baseless, unprecedented and outrageous attacks on him and his administration by the UN, the BBC reported.
"I confirm that the President has directed the Executive Secretary to give notice that (the Philippines is) withdrawing as a state party to the Rome Statute of the ICC," Duterte's spokesperson Harry Roque said.
Roque's statement came a few minutes after Duterte's office issued a draft statement on the move.
The ICC in February began examining alleged crimes committed during the controversial anti-drugs crackdown. ICC chief prosecutor Fatou Bensouda said the court would be looking at reports of extrajudicial killings.
She stressed that the examinations by the ICC -- based in The Hague -- were "not an investigation" but a process of examining information "in order to reach a fully informed determination on whether there is a reasonable basis to proceed with an investigation".
A statement from the Philippines administration said the ICC inquiry was "in violation of due process".
There has been growing international pressure on Duterte about his country's war on drugs, which caused the deaths of thousands.
Police claimed they killed nearly 4,000 drugs suspects, while rights groups suggest the figure could be far higher.