Philippine presidential hopeful Rodrigo Duterte stuck to his guns on Sunday amid outrage over a remark he made about a murdered rape victim, saying he regretted his "gutter language" but would not apologize for being misinterpreted.

A YouTube video appeared over the weekend showing Duterte speaking at a recent rally where he recalled his experience of being a local mayor during a 1989 prison riot in which an Australian missionary visiting the jail was raped and killed.

The video clip showed Duterte, 71, telling supporters he was angry that a "beautiful" woman had been murdered. He said inmates had lined up to rape her and it was a "waste" because as mayor, he should have been first.