President Duterte has had another pop at the United States. Before he departed for Japan, he said he was against the presence of any foreign troops in his country. He also intimated that their Enhanced Defense Cooperation Agreement -- a 2014 pact which was intended to bolster their alliance -- could be in threat.

However, the US said it wants to remain in the country to quell Islamic militancy in the south of the country. US Ambassador to Manila, Philip Goldberg said the security threat in the conflict-plagued region is "very serious".