Philippines President Rodrigo Duterte has threatened to terminate a pact that allows US troops to visit the Philippines, saying "bye-bye America" as he reacted with rage to what he thought was a US decision to scrap a major aid package over human rights concerns.

A US government aid agency, the Millennium Challenge Corporation, said earlier this week that its board had put back a vote on renewing the development assistance package for the Philippines "subject to a further review of concerns around rule of law and civil liberties".

Though the vote has not taken place, Mr Duterte unleashed an expletive-laden tirade upon his arrival in his southern hometown of Davao after back-to-back visits to Cambodia and Singapore.

The most controversial quotes from Rodrigo Duterte Show all 9 1 /9 The most controversial quotes from Rodrigo Duterte The most controversial quotes from Rodrigo Duterte On killing drug addicts “These sons of whores are destroying our children. I warn you, don’t go into that, even if you’re a policeman, because I will really kill you. If you know of any addicts, go ahead and kill them yourself as getting their parents to do it would be too painful” The most controversial quotes from Rodrigo Duterte Message to China “I will go there on my own with a Jet Ski, bringing along with me a [Phillipino] flag and a pole, and once I disembark, I will plant the flag on the runway and tell the Chinese authorities, ‘Kill me’ ” AP The most controversial quotes from Rodrigo Duterte Christmas message to law-breakers “If you do not want to stop, and just continue committing crimes, then this would be your last Merry Christmas” AP The most controversial quotes from Rodrigo Duterte On sex life “I was separated from my wife. I’m not impotent. What am I supposed to do? Let this hang forever? When I take Viagra, it stands up” AFP/Getty Images The most controversial quotes from Rodrigo Duterte On the drugs trade “None of my children are into illegal drugs. But my order is, even if it is a member of my family, ‘kill him'" AP The most controversial quotes from Rodrigo Duterte Insulting the Pope “We were affected by the traffic. It took us five hours. I asked why, they said it was closed. I asked who is coming. They answered, the pope. I wanted to call him: ‘Pope, son of a wh**e, go home. Do not visit us again’” AFP/Getty Images The most controversial quotes from Rodrigo Duterte Joke about rape “I saw her face and I thought, 'What a pity... they raped her, they all lined up. I was mad she was raped but she was so beautiful. I thought, the mayor should have been first” AFP/Getty The most controversial quotes from Rodrigo Duterte Insulting Barack Obama "Mr Obama should be respectful and refrain from throwing questions at me about the killings, or son of a bitch, I will swear at you in that forum" REUTERS The most controversial quotes from Rodrigo Duterte On Abu Sayyaf Islamic militants "If I have to face them, you know I can eat humans. I will really open up your body. Just give me vinegar and salt, and I will eat you. If you annoy me to the fullest... I will eat you alive. Raw" EPA

It came after the outspoken leader told the BBC that he had personally killed three men while mayor of Davao. As president Mr Duterte has instituted and overseen a bloody anti-drugs programme predicated on the extra-judicial killing of addicts and dealers, leaving some 4,500 Filipinos dead over five months.

On the aid package, he said: "We can survive without American money. But you know, America, you might also be put to notice. Prepare to leave the Philippines, prepare for the eventual repeal or the abrogation of the Visiting Forces Agreement."

The 1998 accord governs American forces visiting the Philippines for joint combat exercises.

Mr Duterte added: "You know, tit for tat. If you can do this, so (can) we. It ain't a one-way traffic. Bye-bye America."

The 71-year-old describes himself as a left-wing politician and made similar threats before and after taking office in June. But he and his officials have walked back on many of his public statements, causing confusion.

While calling Americans "sons of bitches" and "hypocrites", Mr Duterte praised China as having "the kindest soul of all" for offering what he said was significant financial assistance.

"So, what do I need America for?" he asked. However, Reuters has reported that China is the biggest source of methamphetamine smuggled into the Philippines.

Mr Duterte also said Russia could be an important ally. "They do not insult people, they do not interfere," he said.

The Philippines had been in line for another aid package after its previous five-year, $434m poverty reduction programme was successfully completed in May under Mr Duterte's predecessor, Benigno Aquino III.

The agency's spokeswoman, Laura Allen, said it would continue to monitor events in the Philippines before the next board review in March 2017.

The decision is among the first signs of how concerns about the rule of law and human rights under Mr Duterte could entail economic costs.

The US government, along with European Union and UN officials, has raised concerns about Mr Duterte's crackdown on illegal drugs.

In his news conference, Mr Duterte was pointedly asked how many crime suspects he has killed in the past when he was still a crime-busting city mayor amid his vague and contradicting accounts of his exploits. The former government prosecutor again gave contrasting replies.

"Maybe one, two, three. I'm saying, maybe my bullets hit them, maybe not, but after the burumbumbumbum, they're all dead," Mr Duterte said.

Replying to another question, he said that he indeed has killed, but did not provide details and tried to justify his actions. "When I tell you now that I killed, do not term them as suspects because all of them died while they were fighting government people."

He asked God for forgiveness in advance, saying he may not have time to pray if he's assassinated.

"God, forgive me for killing these idiots," Mr Duterte said, then blamed God for the presence of criminals.

"You create a human monster so if you are God, why do you have to create these idiots? That's why they die."

He told the BBC: "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."

Mr Duterte, who has had a difficult relationship with President Barack Obama, said he would change his mindset if President-elect Donald Trump appeals to him.

"I have talked to Trump, he was very nice, very courteous," he said. "I could not sense any hostile drift, or even the manner he was saying it, so, in deference, I'll just wait.

"I will let Obama fade away and if he disappears, then I will begin to reassess."

He and Mr Trump acknowledged each other's similarly brash manners, he said. "We talk in the same language," Mr Duterte said.

He recalled that when he told Mr Trump in a recent phone call that "I like your mouth, it's like mine", Mr Trump responded by saying, "Yes, Mr President, we're similar."

"And you know, people with the same feather flock together," Mr Duterte said.