Rodrigo Duterte, a tough-talking mayor who has drawn comparisons to Donald Trump, appeared to have won the Philippines’ presidential election Monday as he piled up a large lead in unofficial returns and a key rival conceded defeat.

Initial vote counts showed Duterte winning by at least 5 million votes, according to the Philippine Star newspaper. The final vote count will be announced this week.

Supporters say Duterte, 71, has a proven track record in fighting drugs and crime, having transformed the city of Davao, which he led for 22 years, from a den of lawlessness into a rare bastion of security in a troubled region. His nickname is “the Punisher.”

Yet Duterte’s rise has shocked the country’s political establishment, and critics have raised concerns about his many profane comments and alleged human rights violations. While campaigning, he joked about rape and infidelity, promised to clean up crime by killing thousands of criminals and warned that he might declare a “revolutionary government” if he does not get his way in Congress. He has acknowledged overseeing death squads, mercenary groups that executed suspected criminals in Davao.