Duterte threatens to pull Philippines out of UN

President Rodrigo Duterte threatened on Sunday to withdraw the Philippines from the United Nations, as he launched another profanity-laced tirade against the organisation for criticising his bloody war on crime.

More than 1,500 people have been killed since Duterte took office and immediately began his law-and-order crackdown, according to police statistics, triggering fierce criticism from the UN and rights groups.

Duterte, a lawyer famous for an acid tongue who has repeatedly told the UN not to interfere, on Sunday stepped up his rhetoric.

"Maybe we?ll just have to decide to separate from the United Nations. If you are that disrespectful, son of a whore, then I will just leave you," Duterte said in a press conference in his home city of Davao that started about 1:00 am.

Duterte said he may even look to set up another international organisation.

"I would invite everybody. I would invite maybe China, the African (nations)," he said.

The UN's special rapporteur on summary executions, Agnes Callamard, last week said Duterte's promise of immunity and bounties to security forces who killed drug suspects violated international law.

UN Secretary-General Ban Ki-moon in June also strongly criticised Duterte, who during the election campaign promised to kill 100,000 people and dump so many bodies in Manila Bay that the fish would grow fat from feeding on them.

"I unequivocally condemn his apparent endorsement of extrajudicial killings, which is illegal and a breach of fundamental rights and freedoms," Ban said.

Duterte frequently peppers his public comments with swear words -- he has also called Pope Francis and the US ambassador to Manila sons of whores -- and days after his election win used typical language to criticise the UN.

Last month Duterte said he may not ratify the Philippines' commitments to a historic UN climate change pact agreed by his predecessor last year.

On Sunday morning Duterte said the UN had done nothing for the Philippines -- ignoring its poverty reduction programmes and enormous help following typhoons and other natural disasters -- as he continued to curse it.

On the day he was sworn into office, Duterte called for people in slums to kill neighbours whom they believed were drug addicts, repeating a campaign line.

His aides have since said such comments are merely hyperbole and not meant to be taken literally.

However nearly 900 people have been murdered by unknown people during Duterte's time in power, with police killing another 665 alleged drug suspects, according to the national police chief.

The killings represent a massive increase on crime deaths before Duterte took office.

Duterte has repeatedly insisted police have only killed in self defence, while maintaining the other deaths are due to drug syndicates killing each other.