It also came days before the Philippines was to appear, along with 13 other countries, before the United Nations Human Rights Council for a periodic review of its rights record. Its antidrug campaign was expected to be a focus of the session.
Mr. Duterte has said that the Philippines would allow Dr. Callamard to carry out an official investigation into the killings if she allowed him to publicly question her as well. She has rejected the condition, and she said on Friday that her trip was not in an official capacity.
But Ernesto Abella, a presidential spokesman, said that Manila would lodge a complaint at the United Nations about Dr. Callamard.
Credit Bullit Marquez/Associated Press
“We are aware that Dr. Callamard is currently in the Philippines, and we are disappointed that in not contacting our government in advance of this visit, she has sent a clear signal that she is not interested in getting an objective perspective on the issues that are the focus of her responsibility,” Mr. Abella said.
Rights groups say the police are behind the thousands of deaths that have been attributed to vigilantes, an assertion denied by Mr. Duterte. Before his election, he had promised to kill 100,000 criminals in his first six months in office and dump so many bodies in Manila Bay that the “fish will grow fat.”
In a speech on Thursday in the southern city of Davao, Mr. Duterte denied having personally killed drug traffickers at any time, even as he admitted issuing threats against them. He said the many deaths could be the handiwork of drug syndicates killing off each other’s men.
But two figures tied to Duterte, a police officer and a professed hit man, have publicly implicated Mr. Duterte in hundreds of killings, and their lawyer has subsequently asked the International Criminal Court, based in The Hague, to prosecute him on charges of mass murder.
In her remarks on Friday, Dr. Callamard did acknowledge that drugs had become a global problem, causing health disorders for 29 million users and weakening the rule of law and governance enough to be identified as a “major threat.”
Those attending the special session last year “repeatedly denounced drug-related corruption, decrying its role in the obstruction of justice, including through intimidation of justice officials,” Dr. Callamard said. “What governments did not commit to last year was the war on drugs approach. Quite the contrary.”
She said that the assembled nations had agreed that such an effort “does not work.” Badly thought-out policies “not only fail to address substantively drug dependency, drug-related criminality and the drug trade, they add more problems,” she said.
Those policies also foster “a regime of impunity, infecting the whole justice sector,” and erode trust in public institutions, Dr. Callamard said, “ultimately leading people to despair.”