The International Criminal Court's chief prosecutor has called for a full investigation into a deadly crackdown on drugs since President Rodrigo Duterte took office.

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

Driving the news: The ICC launched a preliminary inquiry in 2018 into Duterte and his war on drugs following allegations of crimes against humanity.

• Now, outgoing ICC chief prosecutor Fatou Bensouda has asked for judicial authorization to proceed with a full investigation, according to a statement.
• "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.

What they're saying: Duterte's spokesperson said Tuesday he wouldn't cooperate because the country was no longer a member of the ICC, per Reuters.

• "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