Philippine President Rodrigo Duterte will not cooperate with an investigation into the country's bloody war on drugs planned by the International Criminal Court (ICC), his spokesperson said on Tuesday, while families of the victims expressed happiness at the prospect of an international investigation.

Normita Lopez, whose son was a victim of the anti-drugs campaign, said she could not contain her happiness when she learned about the ICC prosecutor's request to open a full investigation into the killings.

"I am happy because I realised that justice never sleeps...