Philippine priests of the Roman Catholic Church, an institution that helped to oust two of the country's leaders in the past, say they are afraid and unsure how to speak out against the war on drugs unleashed by new President Rodrigo Duterte.

In interviews, more than a dozen clergymen in Asia's biggest Catholic nation said they were uncertain how to take a stand against the thousands of killings in a war that has such overwhelming popular support. Challenging the president's campaign could be fraught with danger, some said.

Duterte, who had a 76 percent satisfaction rating in a survey released last week, has quashed opposition to his war on drugs and blasted critics in curse-laden language. More than 3,600 people, mostly small-time drug users and dealers, have died at the hands of police and suspected vigilantes since he took power on June 30.