Rodrigo Duterte purposely skipped a bilateral meeting between US President Barack Obama and leaders from the Association of Southeast Asian Nations (Asean) in Vientiane, Laos last week.

The statement from the Filipino president contradicts the official statement from Malacanang, the presidential palace, which said he was unable to attend because he was under the weather. The fiery Duterte, however, said he snubbed the meeting by choice.

"I intentionally did skipped [those meetings]," Duterte said during the 2016 Metrobank Foundation Outstanding Filipinos awards ceremony on Monday (12 September) night. "I attended all others," he added.

"The reason is not I am anti-West. The reason is not I do not like the Americans. It's simply a matter of principle for me," said Duterte.

The former mayor of Davao City sparked outrage ahead of the gathering after labelling Obama a "son of a whore" following strong criticism from the US over extrajudicial killings in the bloody drugs war, which has claimed nearly 3,000 lives barely three months after it started in July.

The personal attack led to Obama canceling a planned meeting with Duterte, calling him a "colourful guy". On 6 September, Duterte issued a statement expressing regret for his choice of words.

Duterte's strong language during his maiden international foray was not limited to the US president. He also branded UN Secretary-General Ban Ki-Moon a "fool" for raising concerns over human rights violations weeks before the summit in the Laotian capital.

During last night's ceremony, Duterte presented awards to outstanding teachers, soldiers and police officers and reiterated his commitment to the war on drugs in the Philippines. "I did not declare a punitive police action, mind you, against drugs. I declared a war," he said.

The president added that the crackdown will not cease "until the last addict is eliminated" and said he would "assume full responsibility" for law enforcement officials following his orders. "They have my blessings," he was quoted as saying by CNN Philippines. "I'm ready to be arrested."