Philippine president Rodrigo Duterte has threatened to burn down the United Nations, after it condemned his bloody crackdown on suspected drug dealers.

Since he took office in June, around 6,000 people have been killed by police, vigilantes, and mercenaries in the south-east Asian country on Mr Duterte's instructions.

“You go and file a complaint in the United Nations, I will burn down the United Nations if you want," Mr Duterte said, speaking at an army base in the country's southern city of Zamboanga. "I will burn it down if I go to America."

UN human rights experts have been asking the Philippine government to address extrajudicial killings of drug users in the country since August.

In response, Mr Duterte has said he is considering taking the Philippines out of the UN, withdrawing from the International Criminal Court, and ending a major pact with the US.

On Thursday, he called the UN’ human rights chief Zeid Ra’ad al-Hussein an “idiot”, in response to a suggestion by the diplomat that Mr Duterte be investigated for murder after the president said he personally gunned down at least three people when he was a city mayor.

"I’d go around in Davao with a motorcycle, with a big bike around, and I would just patrol the streets, looking for trouble also," he said. "I was really looking for a confrontation so I could kill."

Mr Zeid called on Tuesday for the authorities in the Philippines to begin an investigation after Mr Duterte's boasts.

“It is unthinkable for any functioning judicial system not to launch investigative and judicial proceedings when someone has openly admitted being a killer," Mr Zeid said in a statement.

But Mr Duterte, who is still well-liked within the country, appeared to be enraged by the remarks.

Philippines declares emergency after 46 killed in election violence Show all 10 1 /10 Philippines declares emergency after 46 killed in election violence Philippines declares emergency after 46 killed in election violence Bodies of those killed lie on the ground near their vehicles at the scene of the massacre by Ampatuan, Maguindanao. REUTERS/Erik de Castro Philippines declares emergency after 46 killed in election violence Protesters hold placards and candles for the victims of election-related violence in Maguindanao province, southern Philippines, during a rally in Manila. REUTERS/Cheryl Ravelo Philippines declares emergency after 46 killed in election violence Filipino villagers dig a shallow grave for victims of the massacre in Maguindanao, southern Philippines. REUTERS/Erik de Castro Philippines declares emergency after 46 killed in election violence The wife of a local reporter is led away from his body, at the scene of the massacre on the outskirts of Ampatuan, Maguindanao. REUTERS/Erik de Castro Philippines declares emergency after 46 killed in election violence The bodies of female members of a political clan lie on the ground at the scene of a massacre, which included several journalists, on the outskirts of Ampatuan, Maguindanao in southern Philippines.. REUTERS/Erik de Castro Philippines declares emergency after 46 killed in election violence Photographers clench fists as they offer candles for the victims of election-related violence in Maguindanao province, southern Philippines, during a protest condemning the killings of journalists, outside the Philippine National headquarters in Manila. REUTERS/Cheryl Ravelo Philippines declares emergency after 46 killed in election violence A policeman stands guard at the scene of the massacre. Philippine President Gloria Macapagal Arroyo placed two southern provinces and a city under emergency rule on Tuesday after 24 people were killed in the worst-ever election related violence in the country. REUTERS/Erik de Castro Philippines declares emergency after 46 killed in election violence A student holds a bunch of flowers as prayer offerings for the victims of election-related violence in Maguindanao province, southern Philippines, while shouting anti-government slogans during a protest outside the presidential palace in Manila. REUTERS/Romeo Ranoco Philippines declares emergency after 46 killed in election violence Women light candles for the victims of abduction and killing in Maguindanao province southern Philippines during a rally marking the International Day for the Elimination of Violence against Women in Quezon City Metro Manila. REUTERS/Cheryl Ravelo Philippines declares emergency after 46 killed in election violence A newspaper covers the body of a journalist who lost his life in the massacre in Maguindanao province. REUTERS/Erik de Castro

“You there in the United Nations, you do not know diplomacy,” he said, during a news conference in Manila, the capital, on Thursday. “You do not know how to behave, to be an employee of the United Nations. You do not talk to me like that, you son of a bitch.

“You idiot, you do not tell me what to do,” he continued. “Your understanding of international law is lacking. We are the ones contributing to the United Nations. You morons! You sons of whores! And I pay your salaries. Do not open your mouth there. I employ you.”