President Duterte’s outspoken style and crime-fighting record have made him popular with many Filipinos.
Here are some of his most contentious statement:
Insulting the US president
With China and the Philippines engaged in a dispute over territory, it would be conventional for Mr Duterte to build close ties with the country’s most powerful ally, the US.
But instead, ahead of meeting in Laos he described Barack Obama as a “son of a whore” over suggestions the US president might challenge him on human rights issues.
He succeeded in avoiding the topic in one sense, at least. Mr Obama cancelled the meeting, saying he preferred “constructive, productive conversations”.
Defending drug deaths
A sharp increase in killings of alleged drug dealers and drug users under Mr Duterte’s leadership is no surprise – he promised to do as much during his election campaign. But with thousands now thought to have been killed, he has still run into opposition.
Unsurprisingly, the man who once said he would kill his own children if they took drugs has not backed down.
“Do the lives of 10 of these criminals really matter? If I am the one facing all this grief, would 100 lives of these idiots mean anything to me?” he said.
When UN human rights experts said his encouragement of drug killings amounted to “a crime under international law”, he responded with an expletive-laden tirade, branding the experts “stupid” and threatening to pull out of the UN. He later said his threat was a joke.
A vow to kill 100,000 criminals
Mr Duterte won the presidency because of his success in reducing crime while mayor of Davao.
In a bid to tackle communist insurgents, Davao armed civilian militias, who went on to become death squads targeting others seen as a threat to public order. It was an approach Mr Duterte promised to replicate as president.
“Forget the laws on human rights. If I make it to the presidential palace, I will do just what I did as mayor. You drug pushers, hold-up men and do-nothings, you better go out. Because I’d kill you,” he said at his final campaign rally. “I’ll dump all of you into Manila Bay, and fatten all the fish there.”
