Detained opposition Senator Leila de Lima challenged President Rodrigo Duterte to support an independent probe led by the United Nations into the deaths and "the rash of extrajudicial killings" in his administration's war against illegal drugs.

In a statement on Saturday, February 10, De Lima also welcomed the call of Human Rights Watch (HRW) for the Philippine government to support the said investigation.

De Lima said Duterte "should seriously take heed" of the call of HRW "even just to prove that his administration has nothing to do about the continued surge of drug-related killings in the country."

"Thousands of Filipinos are getting killed, and sadly, President Duterte remains unperturbed," said De Lima. "He chooses to ignore reports of glaring human rights violations and abuses by police and security forces who put law in their hands instead of facing the issue head-on."

"If he has nothing to hide, then it’s high time for the President to support the independent investigation into the human rights violations and abuses incessantly happening under his regime," she added.

On February 1, New York-based HRW said the independent UN-led probe could help clarify the number of deaths in Duterte's "war on drugs."

The Philippine National Police (PNP) reported that as of January 17, 2018, around 3,987 drug suspects died in legitimate police operations since the start of Duterte's term in 2016.

But some watchdog groups offered a different count. De Lima said "nongovernmental groups, such as the Philippine Alliance of Human Rights Advocates and the International Drug Policy Consortium, put the drug war casualties to be more than 12,000, while the Catholic Bishops' Conference of the Philippines estimated the figure could reach more than 13,000."

"We cannot just accept the data coming from the PNP, especially now that dozens of suspected drug offenders have reportedly been killed in the past months since PNP resumed its role in the government’s drug war," said De Lima, a former justice secretary and Commission on Human Rights chairperson.

Duterte returned the police to the anti-drug operations in December last year, after a second brief suspension of the operations due to controversies. The PNP relaunched its Oplan Tokhang the following month, guided by new protocols.

Meanwhile, the International Criminal Court (ICC) has begun preliminary examinations to see whether there is sufficient evidence to establish that a complaint filed against Duterte and his administration regarding the drug war falls under its jurisdiction.