President Rodrigo Duterte joined Manny Pacquiao's birthday celebration on Saturday in General Santos City where he wished the world boxing champion and senator well, then went on to lash out at his detractors.

Duterte was coming off a trip in Zamboanga City earlier on Saturday when he met with wounded soldiers at a military camp. He brought up familiar talking points there, touching on plans to sever military ties with the US and critics of his war on illegal drugs.

He delivered the same message in General Santos City using the same fiery style that has elicited applause from his supporters but has upset the West, particularly the United States and the United Nations.

At Pacquiao's party, Duterte focused on his personal and national agenda, and made little reference to the birthday celebrant, at least that was what was shown in the televised speech.

Duterte did call Pacquiao "president-to-be," which drew resounding approval from the cheering crowd.