THE HAGUE, Netherlands -- The arrest of former Philippine president Rodrigo Duterte is an important moment for alleged victims of his "war on drugs", International Criminal Court Chief Prosecutor Karim Khan said on Wednesday.

The fact the ICC arrest warrant has been carried out "is important to victims. It means a lot, I think, to victims," said Khan in a statement.

"Many say that international law is not as strong as we want, and I agree with that. But as I also repeatedly emphasise, international law is not as weak as some may think," added Khan.

"When we come together... the rule of law can prevail," said the prosecutor.

Duterte was handed to the ICC on Wednesday after it issued a warrant for his arrest over his deadly crackdown on drugs.

READ: Duterte touches down in the Netherlands, now in ICC custody

"Mr Rodrigo Roa Duterte... was surrendered to the custody of the International Criminal Court," the ICC said in a statement. "He was arrested by the authorities of the Republic of the Philippines in accordance with an arrest warrant issued... for charges of murder as a crime against humanity."

The ICC, based in The Hague, has said there were "reasonable grounds" to believe Duterte committed the crime against humanity of murder as an "indirect co-perpetrator" during the anti-drug campaign that rights groups estimate killed tens of thousands.

The 79-year-old is the first Asian former head of state to face charges at the ICC, which rules on the world's worst crimes, including war crimes, crimes against humanity and genocide.

Once in ICC custody, Duterte will be taken to a detention center before an initial appearance likely to be scheduled in the coming days.

© Agence France-Presse