Philippine President Rodrigo Duterte "will not cooperate" with an International Criminal Court investigation into his government's deadly nationwide crackdown on drugs, his spokesperson said Tuesday, per Reuters.

Why it matters: Official government data shows more than 6,100 people have died in police drug operations in the Philippines since Duterte took office in 2016, but rights groups say the figure is likely to be much higher.

Driving the news: Outgoing ICC chief prosecutor Fatou Bensouda launched a preliminary inquiry in 2018 into Duterte and his war in drugs following allegations of crimes against humanity.

• Now, she has asked for judicial authorization to proceed with a full investigation.
• "I have determined that there is a reasonable basis to believe that the crime against humanity of murder has been committed on the territory of the Philippines between 1 July 2016 and 16 March 2019 in the context of the Government of Philippines 'war on drugs' campaign," Bensouda said in a statement.

What they're saying: Duterte's spokesperson Harry Roque told a news conference the Philippine government wouldn't cooperate because the country was no longer a member of the ICC, Reuters reports.

• "We do not need foreigners to investigate killings in the drug war because the legal system is working in the Philippines," Roque said, according to Reuters, calling the investigation "legally erroneous and politically motivated."

What to watch: British lawyer Karim Khan is due to take over as the ICC's chief prosecutor on Wednesday.

Go deeper: How Duterte's bloody drug war engulfed the Philippines