In two fiery speeches to mark his 100 days in office, Duterte repeatedly raised the prospect of local or foreign opponents seeking to remove him from power in an effort to stop the violence.

But he insisted he would not be intimidated and that his campaign against drugs, in which an average of more than 33 people a day are being killed, would not end.

"You want to oust me? You want to use the CIA? Go ahead," Duterte said in a speech in his southern home town of Davao city, referring to the Central Intelligence Agency, while railing against US President Barack Obama and other critics.

Last month Duterte accused the CIA of plotting to kill him, but gave no specifics.

Also on Friday he referred to a local newspaper columnist who warned a "People Power" movement could form to try and topple Duterte, using the term coined for the revolution that overthrew dictator Ferdinand Marcos in 1986.