The Philippines president said he did it as a mayor to encourage police to do the same.
Philippines President Rodrigo Duterte said he personally killed drug suspects when he was a mayor of his home city Davao, saying he did so to show police "if I can do it, why can't you."
Human rights groups for some time have accused Duterte of taking part in extrajudicial killings. He admitted to so doing on Monday while addressing a gathering of businessmen.
He said one-third of the people killed to date in his so-called war against drug traffickers were executed by police.
Police and vigilantes are accused of killing more than 5,000 people since President Duterte launched his drug war after coming to power in June.