Malaysia, the Philippines, Vietnam, Japan, and China all claim parts of the South China Sea.
Manila is looking to ease tensions with Asia's top economic power.
"Here's the shocker: I will kill you. I will really kill you. And that's why the rapporteur of the U.N. is here, investigating extrajudicial killing," Duterte said.
The Philippines is currently involved in a maritime dispute with China over its interests in the South China Sea, although Duterte is attempting to forge closer ties with the country.
The notoriously blunt Duterte said the Southeast Asia region was extremely worried about tensions between the United States and North Korea, and said one misstep would be a "catastrophe."
Committing the U.S. to a potentially escalating conflict is not a decision for one person alone.
73 percent of respondents said they were concerned that they or someone they know will be a victim of the war on drugs.
The militant leader was killed after he traveled to a tourist hot spot on a hostage-taking expedition.
Trump has expressed his admiration for brutal strongmen like el-Sissi, Putin and Duterte.
"Our forecast for 2017 is that the threat in this region will grow because of the creation of an IS nucleus in the southern Philippines," defense expert Rohan Gunaratna said.
The New York Times article, written by Richard C. Paddock, touched on Duterte's childhood.
"It will crash like a rudderless plane flown by witless pilots" say Duterte supporters
There are 31 hostages currently being held by Abu Sayyaf.
The group, which murdered two Canadians last year, demanded a ransom for his release.
Young children could face adult charges and even the death penalty.