This last comment — absolving his soldiers for any future rapes — was widely reported as a joke, and if it was, it wouldn't be the ruler's first attempt at the genre.
Before he won the presidency last year, Duterte joked that he “should have been first” in the gang rape of a woman who was held hostage, raped and killed in the 1980s.
As Travis M. Andrews noted for The Washington Post, Duterte's lead widened after the comment. Since then, violence has infused the rhetoric and actions of his presidency.
“Hitler massacred 3 million Jews. Now, there are 3 million drug addicts. … I'd be happy to slaughter them,” he told reporters a few months after winning the election.
Thousands have been killed in Duterte's drug war — some by vigilantes, and some gunned down by police on government orders.
Lately, he has expanded his attention from drugs to a years-long spate of battles between Philippine forces and Muslim insurgent groups on the southern island of Mindanao, where one of Asia's most wanted militants is believed to be hiding.
When Duterte declared martial law on the island and its 20 million people Tuesday, he cited the fictitious beheading of a police chief — who is still alive — to explain his decision.
A day later, he threatened to expand martial law across the country, and told his troops to “spare no one” who violently resists government forces.
The president often appears to revel in his bloody reputation. He has called himself more brutal than the Islamic State, and in December claimed to have thrown a criminal out of a helicopter.
He later said he was joking about the helicopter.
Many condemned his comments last week.
“Rape is not a joke,” a women's political party in the country said in a statement, according to the BBC. “Martial law and the heightened vulnerability to military abuse that it brings to women and children are not a joke either.”
A Human Rights Watch representative told the outlet the president had signaled to his soldiers that they could carry out abuses under martial law.
But Duterte has not shown much concern for his international reputation in the past. He has criticized former president Barack Obama and Pope Francis.
And he once called Donald Trump “a bigot,” before the two men became presidents.
They used nicer words for each other in a phone call last month, according to a leaked transcript of the conversation, in which Trump praised Duterte's drug war.
Duterte invited Trump to the Philippines at the end of the call, according to the transcript.
Trump, in turn invited Duterte to the Oval Office and said he was “a good man.”
The Associated Press contributed to this report.