The US ambassador to the Philippines called Tuesday for "full accountability" following the alleged murder by local police of a 17-year-old boy as part of President Rodrigo Duterte's drug war.
The killing of Kian Delos Santos last week triggered rare protests against Duterte's controversial but popular campaign to eradicate drugs, with critics saying it highlighted rampant rights abuses by police enforcing the crackdown.
My condolences go out to the family and friends of Kian. Hope that the investigations lead to full accountability.
— Ambassador Sung Kim (@USAmbManila) August 22, 2017
Duterte easily won presidential elections last year after promising to wipe out drugs in the country by waging an unprecedented crackdown in which tens of thousands of people would die.
Since he came to office 14 months ago, police have reported killing 3,500 people in anti-drug operations.
More than 2,000 other people have been killed in drug-related crimes and thousands more murdered in unexplained circumstances, according to police data.
The United States, a longtime ally of the Philippines, had under then-President Barack Obama led international criticism of Duterte's drug war.
Duterte reacted furiously and used the criticism as one reason for weakening his nation's alliance with the United States.
Duterte has said relations with the United States are better under Donald Trump, who has praised him for doing an "unbelievable job on the drug problem".
Kim's predecessor had repeatedly criticised Duterte in public.
Kim, who has been the ambassador since late last year, had sought to repair relations and refrained from publicly criticizing the drug war.
While rights groups say Duterte may be orchestrating a crime against humanity, many Filipinos support the charismatic president and his efforts to fight crime.
However Delos Santos's death has dominated the media, and even some of Duterte's cabinet members and supporters have spoken out against the killing.
Police said Delos Santos was a drug courier who fired at them while resisting arrest.
However CCTV footage emerged of two policemen dragging the unarmed boy away moments before he was killed.
The public attorney's office on Monday said a forensic investigation found Delos Santos was shot in his back and ear, and that the evidence pointed to an "intentional killing".
Defence Secretary Delfin Lorenzana on Tuesday added his voice to the condemnation, following similar comments from the education minister.
"Whether or not he was involved in the use or trafficking of illegal drugs, he did not deserve to die in the manner that he did," Lorenzana said in a statement.
"If the allegations of foul play are proven then the perpetrators must be brought to justice."
The Philippine Senate on Thursday will begin its investigation into Delos Santos's death following an outcry from different sectors.
Over the weekend, the two top leaders of the influential Catholic Church called for an end to the bloodshed as they urged the faithful to "stop consenting to the killings".
Duterte on Monday said policemen who killed Delos Santos would be jailed if convicted.
However he has also repeatedly vowed to pardon officers if they are found guilty of murder while fighting his drug war.
Duterte last month ordered the reinstatement of policemen who, according to the National Bureau of Investigation, murdered a politician facing drug charges inside his jail cell.