As Rodrigo Duterte was sworn in as the Philippines' 16th president on 30 June 2016, he delivered a speech – one hand on the Bible – in which he promised a "relentless" and "sustained" fight against corruption, criminality and illegal drugs. He conceded that many believe his methods "are unorthodox and verge on the illegal" – however, he said he knew right from wrong and would abide by the rule of law.

Rodrigo Duterte Du30 philippines
Rodrigo Duterte Du30 philippines
Rodrigo Duterte Du30 philippines
Rodrigo Duterte Du30 philippines
Rodrigo Duterte Du30 philippines

Duterte was previously mayor of the city of Davao, where, according to human-rights groups, death squads have killed at least 1,400 people since 1998, most of them drug dealers, addicts, petty criminals and street children. Duterte denies any involvement in vigilante killings.

In February 2017, Arturo Lascanas, a retired policeman, testified before a Senate hearing that he killed around 200 people under Rodrigo Duterte's orders when he was the mayor of Davao City.

In December 2016 Duterte told a gathering of businessmen that as mayor of Davao City he "personally" killed criminals as he prowled the streets. He later admitted killing three men involved in a kidnapping case during a police gunfight in the late 1980s – although he further clarified that he was unsure whether the bullets from his M16 rifle killed the suspects.

The brash-talking president suggested that he used to roam around his sprawling city as mayor on a big motorcycle to look for criminals to kill so policemen would emulate him. "In Davao, I used to do it personally. Just to show to the guys that, if I can do it, why can't you?" Duterte said. "I go around in Davao with a motorcycle, with a big bike around, and I would just patrol the streets looking for trouble. I was really looking for an encounter to be able to kill."

Justice Secretary Vitaliano Aguirre II has defended Duterte, saying the president often exaggerates killings of criminals to send a chilling warning to lawbreakers. The photos in this gallery show Duterte handling machine guns in the 1980s and 1990s.

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Late 1980s: Mayor Rodrigo Duterte (L) inspects an assault rifle at a shooting range in Davao City in the southern Philippines with regional police chief Miguel Abaya and Metrodiscom chief Franco CalidaRenato Lumawag/Reuters
Rodrigo Duterte Du30 philippines
Mid-1990s: Mayor Rodrigo Duterte poses with his Uzi sub-machine gun in the mountainous village of Carmen in the Baguio District of Davao City in the southern PhilippinesRenato Lumawag/Reuters
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Early 1990s: Mayor Rodrigo Duterte assists a policeman to direct street traffic in downtown Davao City in the southern PhilippinesRenato Lumawag/Reuters
Rodrigo Duterte Du30 philippines
1997: Mayor Rodrigo Duterte inspects the assault rifle of Senior Inspector Ronald Dela Rosa at a crime scene in the village of Tamugan in Davao City in the southern Philippines. Looking on is Davao Police Chief Isidro LapenaRenato Lumawag/Reuters
Rodrigo Duterte Du30 philippines
1987: Rodrigo Duterte poses for a picture in Davao City in the southern Philippines, following his appointment as vice mayorRenato Lumawag/Reuters
Rodrigo Duterte Du30 philippines
March 1998: Soldiers listen as Davao City mayor Rodrigo Duterte gives a lecture on fighting the illegal drug trade during an anti-drug seminar in Davao City in southern PhilippinesRenato Lumawag/Reuters
Rodrigo Duterte Du30 philippines
24 August 2016: Philippine President Rodrigo Duterte makes a fist bump gesture with soldiers during a visit at Capinpin military camp in Tanay, Rizal in the PhilippinesErik de Castro/Reuters
Rodrigo Duterte Du30 philippines
1997: Davao Mayor Zafiro Respicio (4th L) and Vice Mayor Rodrigo Duterte (2nd R) talk to feuding Bagobo tribes to settle a Pangayaw - or tribal war - in the hinterlands of Davao city in the southern PhilippinesRenato Lumawag/Reuters
Rodrigo Duterte Du30 philippines
8 February 2004: Women from the slums of Davao hold pictures of their dead or missing sons, who were involved in petty theft or the drug trade. The mothers blame Davao city mayor Rodrigo Duterte for what happened to their sons, whom they believe were summarily executedRomeo Ranoco/Reuters

Duterte has also revealed that he once threw a suspected kidnapper out of a moving helicopter when he was mayor of Davao City. After visiting areas affected by Typhoon Nina, Duterte gave a speech at the Camarines Sur provincial capital, during which he elaborated on his plans to crackdown on corruption within the government. "If you are corrupt I will fetch you with a helicopter and I will throw you out on the way to Manila," he said. "I have done that before, why should I not do it again?"

The former crime-busting mayor of the southern city of Davao had said that the war on drugs would be over within six months but has since pushed back the deadline. He has said that he will continue "until the last pusher drops dead".