MANILA (NYTIMES) - Philippines President Rodrigo Duterte on Thursday (Sept 27) said for the first time that extrajudicial killings had happened under his government's brutal war on drugs, an admission that could bolster two cases filed against him at the International Criminal Court.

In a rambling speech before government executives at the presidential palace, Mr Duterte again touched on the government's drug war that has left thousands dead, a common theme in his two-year-old presidency.

He said he had challenged the country's military and police brass to remove him from office if they were not satisfied with the way he was running the country.

"I told the military, what is my fault? Did I steal even one peso?" Mr Duterte said. "My only sin is the extrajudicial killings." He did not elaborate.

But it was the first time Mr Duterte publicly acknowledged that extrajudicial killings by the authorities had occurred in his presidency, and it added credibility to claims by rights groups that he had engineered mass killings of alleged drug suspects.

Two criminal complaints against the President have been filed with the International Criminal Court, based in The Hague. Angered by what he called foreign interference in the Philippines' internal affairs, Mr Duterte subsequently pulled out of an international treaty that established the court.

The Philippine National Police estimate that they have killed about 4,500 users and dealers in drug enforcement operations in the past two years, and insist that all of the killings were legitimate uses of force.

Rights groups, including the New York-based Human Rights Watch, estimate that more than 12,000 people have died in the drug war, many of them victims of summary execution by the police.

Mr Romel Bagares, a lawyer for a human rights group, the Philippine Coalition for the International Criminal Court, noted that while Mr Duterte was known for his off-the-cuff remarks, Thursday's comments were "by far his most direct admission of being responsible for" extrajudicial killings.

"And I am surprised there has been no retraction of any kind from the palace since he made them," he said. "I'm sure this would also be of extreme interest to the ICC's Office of the Trial Prosecutor now making a preliminary investigation of his drug war."