Whether Philippine President Rodrigo Duterte aims to shock, inspire or just amuse, deciphering his blunt and often unpredictable rhetoric is a potential challenge for those dealing with the new leader.

Today US President Barack Obama shrugged off a rude remark from his Philippine counterpart, but the outburst from Duterte could derail a scheduled meeting between the two leaders this week.

Duterte threatened to curse out the US commander in chief if Obama brings up the extrajudicial killings by Philippine authorities in a sweeping crackdown on drug trafficking.

Speaking to reporters, Duterte, who took office in June, said the Philippines is a "sovereign state and we have long ceased to be a colony," according to AP.


He added that: "I do not have any master except the Filipino people, nobody but nobody. You must be respectful. Do not just throw questions. 'Putang ina' I will swear at you in that forum." That is the Tagalog phrase for "son of a wh*re."

Asked to respond during a news conference after the Group of 20 Summit in China, Obama said he had been told of Duterte's comments, but the US President shrugged it off as another in a line of "colourful statements" from Duterte.

"Clearly, he's a colourful guy," Obama said. The President added that he had asked his staff to speak to their Philippine counterparts to "make sure if I'm having a meeting, it's productive and we're getting something done". Obama called the Philippines a close "friend and ally" of the United States.

More than 2000 suspected drug dealers have been killed since Duterte took office, and Obama said he would not shy away from the topic of "international norms" when it comes to due process rights when speaking with Duterte. They are scheduled to meet during the Association of Southeast Asian Nations summit in Laos this week.

"We recognise the significant burden the drug trade plays in the Philippines and around the world," Obama said. But "we will always assert the need to have due process and engage the fight against drugs in a way that is consistent with basic international norms. Undoubtedly, if and when we have a meeting, this is going to be something that's brought up. My expectation, my hope, is that it could be dealt with constructively."

He suggested, however, that the meeting was predicated on whether Duterte was willing to have a serious conversation.

"I'm just going to make an assessment," Obama said.

When it comes to the war on illegal drugs, events have unfolded the way Duterte promised, with lethal police operations since he was sworn in on June 30. On his pledge to invest heavily in infrastructure, Duterte has impressed overseas investors, who have pumped US$1.1 billion into the nation's shares over the last three months.

But on a range of other issues, Duterte has sent more confusing signals. Some have been as innocuous as his choice of residence. Others have carried more weight, such as whether the Philippines intends to negotiate with China over territory in the South China Sea, or whether the country can live without mining, or if he really means to ban online gambling.

"We have to get used to the president - his ranting and his off-the-cuff remarks - but we'll see," said Joey Cuyegkeng, an economist at ING Groep in Manila. "Sometimes he recovers from those things."

Duterte's spokesman, Ernesto Abella, said that while the President might use hyperbole and "edgy" or "morbid" humour in his public addresses, he was a leader who prioritised an orderly society, national sovereignty and the common good. "His North Star is the well-being of a prosperous, just and peaceful nation," Abella said in a text message.

Either way, here are seven matters on which Duterte has shown odd behaviour for a leader and appeared to flip-flop since he came to power.

1 Playing games

At his first Cabinet meeting, Duterte ordered a halt to online gambling. He followed up with a speech on August 3 singling out then-PhilWeb Corp. Chairman Roberto Ongpin as he promised to curb big business influence on government. The Philippine gaming regulator decided not to renew PhilWeb's contract supplying so-called e-games cafes, which offer patrons electronic casino games such as baccarat, blackjack, slot machines and video poker.

Then on August 24, Duterte said the Philippines would allow online gambling to resume, provided operators paid proper taxes and electronic casinos were located away from schools and churches.

2 Separating from the UN

At 3 am local time on August 21, Duterte said he may withdraw the Philippines from the United Nations, after UN officials criticised his war on illegal drugs. "Take us out of your organisation. You have done nothing anyway," Duterte, 71, said. The following day, Foreign Affairs Secretary Perfecto Yasay issued a clarification, saying the Philippines remained committed to the international body. "Can't you take a joke?," Duterte asked on August 23.

3 Navigating the South China Sea

After China refused to acknowledge an international court ruling in favour of the Philippines that rejected China's claims to more than 80 per cent of the South China Sea, Duterte responded first by sticking to his pledge not to "flaunt or taunt" the decision. On August 23 Duterte said he expected to have bilateral talks with China within the year. But the next day, he warned China against invading Philippine territory, saying "it will be bloody and we will not give it to them easily". Duterte is due to meet senior Chinese officials at the Association of Southeast Asian Nations summit.

4 Living without mining

Riffing on the subject of mining regulations in early August, Duterte told the country's miners, the world's biggest suppliers of nickel, that the Philippines could live without them. "You obey or we will survive as a nation without you," Duterte said. Three days later, in a televised speech in the southern city of Davao, Duterte tweaked his threat. He suggested that further mining permits would still be granted, while stressing there must be a limit to mining activities, saying it was time to reconfigure wealth distribution in the Philippines.

5 Stance on Abu Sayyaf

A Philippine soldier keeps watch at a blast site at a night market that has left several people dead and wounded others in southern Davao city, Philippines, late last week. Photo / AP
A Philippine soldier keeps watch at a blast site at a night market that has left several people dead and wounded others in southern Davao city, Philippines, late last week. Photo / AP

"You've never heard me say that they are criminals," Duterte said in a July 8 speech in Davao on the subject of Islamic insurgent group Abu Sayyaf, which operates in the southwestern Philippines. With a history of bombings, extortion and targeted assassinations, Duterte said Abu Sayyaf "were driven to desperation" by failed promises made under previous governments.

Still, by the end of July he referred to Abu Sayyaf as "enemies that have to be destroyed," and last week reiterated the bandits must be tackled: "Seek them out in their lairs and destroy them - the Abu Sayyaf. Destroy them, period."

6 Where to live

In the run-up to his inauguration, Duterte often said he planned to take a commercial flight each morning from his home in Davao to the capital Manila, and return every evening. "My bed is here. My room is here. My home is my comfort zone. It's important that I can sleep and take a shower comfortably," he said in late May. Then in early July, Duterte announced his decision to follow predecessor Benigno Aquino by making the palace in Malacanang his official residence.

7 Climate change

In mid July, Duterte said his Administration would not honour the Paris pact on climate change that his country adopted along with 200 or so nations last December, arguing the Philippines wasn't sufficiently industrialised and its requirements differed. Just days later Duterte changed tack, saying the Philippines would be willing to talk about signing the pact if it took into account his plans for the economy.

- additional reporting Bloomberg