More than 1,900 people have been killed in Duterte's war on drugs since he came to power seven weeks ago
Philippines President Rodrigo Duterte on Thursday accused a senator heading an inquiry into extra-judicial drug killings of taking bribes from jailed drug lords, which she immediately denied.
The senator, Leila de Lima, who has criticised the surge of killings and called for the Senate investigation, appealed to Duterte in a news conference to "stop this madness".
More than 1,900 people have been killed in Duterte's war on drugs since he came to power seven weeks ago, according to police figures. Police say the toll of about 36 people a day is a result of drug dealers resisting arrest or gang feuds.
Duterte, who won a May election on a promise to wipe out drugs and dealers, last month named about 160 officials, judges, police and soldiers who he said were protecting drug traffickers or selling drugs in their communities.
On Thursday, he turned his anger on De Lima.
"De Lima, you are finished," Duterte told a news conference in Davao City in the south of the country where he used to be mayor and built his reputation as a ruthless crime fighter.
Duterte handed the media a diagram purportedly showing links between officials and politicians and big drug dealers locked up in the country's main prison.
At the top of the list was de Lima.
"De Lima is undergoing a nightmare now," Duterte said.
De Lima later held her own news conference and denied the president's accusations as "nonsense and baseless". She said the diagram showing her atop a web of graft and drugs was "garbage".
She said was the only one speaking out against Duterte's war on drugs and she would not be threatened.
"Stop this madness," she pleaded to the president.
"It's as if this war against drugs has turned into a war versus de Lima ... It's like he's really bent on destroying me at all costs. I hope he stops it."
This month, Duterte said de Lima was having an affair with her driver. She declined to comment on the issue.
Also on the president's diagram was a congressman, who is also a retired police general and former provincial governor, a former deputy justice minister and his brother, a former prison official, and a civilian, who was de Lima's driver.
The United States, a close ally of the Philippines, said this week it was "deeply concerned" about the reports of extra-judicial drug killings and it urged Duterte's government to ensure that law-enforcement efforts "comply with its human rights obligation".
The crackdown and some strongly worded criticism Duterte has made of the United States since coming to power present a dilemma for Washington, which has been seeking to forge unity among allies in Asia in the face of an increasingly assertive China, especially in the strategic South China Sea.
Last week, two U.N. human rights experts urged Manila to stop the extra-judicial executions and killings. Duterte responded by threatening to leave the United Nations.
The Philippines summoned the Chinese ambassador this week to explain reports that traffickers were bringing narcotics from China.
"This fight against drugs will continue to the last day of my term," Duterte told the news conference.