Philippines president

Rodrigo Duterte was met with a roar of approval and chants of "Duterte, Duterte" when he took to the stage in Singapore to address members of the Filipino community.

He said he would not stop "until the last drug pusher and the last drug lord are..." at which point he drew his finger across his neck in a dramatic execution-style gesture.

"Look; it can never be a crime to say, 'I will kill you if you destroy my country,'" he added, asking the appreciative crowd to look at the crime rate. "Almost gone," he said. "Ask your relatives back home."

He said: "I killed about three of them... I don't know how many bullets from my gun went inside their bodies. It happened and I cannot lie about it."

His statement came hours after his spokesman denied that Mr Duterte had personally killed anyone.

The recent controversy began on Wednesday at the president's palace.

He told a group of business leaders gathered there: "In Davao I used to do it [kill] personally. Just to show to the guys [police] that if I can do it why can't you.

The inspiration for cleaning up his vocabulary came from God himself, Duterte said, as he was flying back to the Philippines from a state visit to Japan.

"Everybody was asleep, snoring, but a voice said... 'If you don't stop (cursing), I will bring this plane down now.' And I said, 'Who is this?' So, of course, it's God," the President recounted after he landed Thursday at Davao International Airport.

Addressing a press conference in Davao City after his return from a state visit to China, Duterte said:

"It is not severance of ties. You say severance of ties, you cut the diplomatic relations. I cannot do that.

"Why? It is in the best interest of my country that we maintain that relationship. Why? Because there are many Filipinos in the United States. Well, Americans of Filipino ancestry.

"Why? Because the people of my country [are] not ready to accept. I said separation -- what I was really saying was separation of a foreign policy. "

Duterte said Saturday he did not realize the severity of the problem until he became president. He's been accused of ordering or encouraging hundreds of killings of drug dealers and users since taking office in June.

"But the problem is ... I cannot kill them all ... even if I wanted to," he told reporters. "I did not have any idea that there were hundreds of thousands of people already in the drug business and what makes it worse is that they are operated now by people in government -- especially those elected positions."

Death squad

The controversial former mayor of Davao City, 71, overthrew the political establishment, promising a "bloody war" on crime and action on corruption.

In his inaugural speech he promised to make sweeping changes to the country's political system.

"I see the erosion of the people's trust in their country's leaders," he said.

"The erosion of faith in our judicial system. The erosion of confidence in the capacity of our public servants to make the people's lives better, safer and healthier."