MANILA (AFP) - Philippine President Rodrigo Duterte said on Tuesday (Oct 11) he would soon visit China and hoped to also travel to Russia, as he again criticised long-time ally the United States for "arrogance".

"China has repeatedly invited me. I have accepted the offer," Mr Duterte said in a speech at the presidential palace.

Mr Duterte gave no specific dates for visiting China, but said it would take place before he went to Japan.

The Japanese government announced on Tuesday that Mr Duterte would visit Japan from October 25 to 27.

Mr Duterte said he had originally planned to visit Japan, the Philippines' biggest source of foreign aid, ahead of China.

However, he explained that Japan offered a "definite" date, then China told Mr Duterte there was a "vacancy" earlier and so he accepted.

Mr Duterte also said that, after Japan, "probably, I will go to Russia".

The trip will be Mr Duterte's first outside of South-east Asia since assuming the presidency on June 30, signalling the importance he places on improving relations with Beijing that had soured because of a territorial dispute in the South China Sea.

Mr Duterte has looked to build closer ties with Russia as well as China, while launching repeated tirades against the US, the Philippines' former colonial ruler and defence ally.

Mr Duterte on Tuesday again gave a lengthy critique of the US, branding them as "arrogant" and powerless to stop Russia's seizure of Crimea from Ukraine.

His tirades have been largely in response to US criticism of Mr Duterte's war on crime, which has claimed more than 3,300 lives.

Mr Duterte has cancelled joint patrols with the US, said he may scrap a defence pact that allows thousands of US troops to rotate through the Philippines, and threatened to eventually cut ties completely.

Mr Duterte has branded US President Barack Obama a "son of a whore" for expressing concern about human rights in the drug war.

In contrast, he has described Chinese leader Xi Jinping as "a great president", and praised China and Russia for showing respect in not criticising his crackdown.

"Eventually, I might in my term break up with America. I would rather go to Russia or to China. Even if we do not agree with their ideology, they have respect for the people. Respect is important," Mr Duterte said this month.

The Philippines had long been regarded as one of Washington's most loyal allies in Asia, with the two nations bound by a mutual defence pact signed in 1951.

Mr Duterte's predecessor, Mr Benigno Aquino, sought to draw the US even closer in a bid to counter Chinese efforts to take control of the South China Sea.

China claims nearly all of the sea, even waters close to the Philippines and other South-east Asian nations, and has in recent years built artificial islands in the disputed areas capable of hosting military bases.

The 2014 defence agreement and the joint patrols were key to Mr Aquino's strategy to contain China.

Mr Aquino further angered China by filing a case with a UN-backed tribunal in 2013 against Beijing's claims to most of the sea.

In July, shortly after Mr Duterte took office, the tribunal ruled in favour of the Philippines, saying China's claims had no legal basis and its construction of artificial islands in disputed waters was illegal.

But Mr Duterte vowed not to "taunt or flaunt" the verdict and to seek a "soft landing" with China on the issue.

He has launched negotiations with China over the dispute, a tactic rejected by Mr Aquino.

China has welcomed Mr Duterte's overtures.

"The clouds are fading away. The sun is rising over the horizon and will shine beautifully on the new chapter of bilateral relations," Chinese Ambassador to Manila Zhao Jianhua said this month.