BEVERLY HILLS - Boxing icon Manny Pacquiao issued staunch support for President Rodrigo Duterte on Thursday after the Asian strongman clashed with US leader Barack Obama over the country's bloody crime crackdown.

Duterte and Obama have traded blows in a bruising diplomatic bust-up this week, culminating in a stand-off at an Asian summit over the crackdown in the Philippines which has left 3,000 dead.

Pacquiao, elected to the Senate this year and a political ally of Duterte, did not hesitate to wade into the row on Thursday as he spoke to journalists in Beverly Hills.

Asked for his views on the diplomatic furor -- which at one point saw Obama cancel a meeting with Duterte after the Filipino leader attacked him in a curse-filled rant -- Pacquiao's position was clear.

"My president apologized for what he said," Pacquiao said. "My President sometimes says words that people around him don't like. But I always support my President."

Asked if he backed Duterte's anti-crime policies -- which have seen an average of 44 people die every day in the Philippines at the hands of police and shadowy death squads -- Pacquiao replied: "Of course."

"We want to stop all the drugs in the Philippines. We want to stop that. We're taking seriously fighting against illegal drugs.

"It's easy to say comments about the Philippines. But to be there and fight illegal drugs is not easy," added Pacquiao, noting that he backed the restoration of capital punishment in his homeland.

Speaking at a summit in Laos, Obama had urged Duterte to conduct his crime crackdown "the right way" with respect for the rule of law.

The US leader's remarks came after Duterte had given a fiery address to leaders of the 18-nation East Asia group, including Obama, which descended into a tirade about US military killings in the Philippines when it was an American colony between 1898 and 1946.