As Rodrigo Duterte was sworn in as the Philippines' 16th president on Thursday (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.

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.

The dead bodies of dozens of suspected drug dealers have turned up across the Philippines in recent weeks. Some were killed in gunfights with police, while others were mysteriously dumped on the streets. Handwritten warning signs have been left on some of the corpses.

The numbers of bodies have spiked since Duterte swept to power on promises to wipe out crime and corruption within six months. That pledge won him huge support but also sparked concerns about vigilante justice.

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The dead body of a suspected drug dealer lies on the ground in Manila, covered by a placard reading 'Chinese drug lord'AFP

On average, at least one person has been shot dead by police or anonymous vigilantes every day since the 9 May election that swept Duterte to power, an escalation from the first four months of the year when the rate was about two a week.

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Police exam a dead body after a drug bust in Manila ended in a shootoutDondi Tawatao/Getty
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A police crime scene operative gathers forensic evidence after three suspected drug dealers were killed when a drug bust operation ended in a shootoutNoel Celis/AFP

Nicknamed 'Duterte Harry', the hardline president has been quoted as warning drug users: "If you're into drugs, I'm sorry. I'll have to apologise to your family because you'll surely get killed." After police executed a drug lord in a northern province, Duterte travelled there to congratulate them and gave them a reward of $6,000 (about £4,500).

The man Duterte has chosen to be the country's police chief, Ronald dela Rosa, concedes that some recent killings may have been carried out by officers involved in the drugs business who were covering their tracks so that the new president does not go after them. "That could be true," he told Reuters. "Some police officers are shifting from drug protectors to drug punishers."

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A member of the National Capital Region Police Office drug unit covers his face as he is detained for allegedly reselling seized substances in ManilaRomeo Ranoco/Reuters
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A bag of methamphetamine, known locally as shabu, is displayed by a National Bureau of Investigation agent after a raid on the home of a police officer and member of the anti-drugs unit in ManilaRomeo Ranoco/Reuters
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Law enforcement officers queue up during a surprise mandatory drug test at a police station in ManilaNoel Celis/AFP

However, dela Rosa said most of the victims in the recent wave of killings were shot by police in self-defence. "I have no problem how many people die in legitimate police operations, the police have a right to defend themselves," he said. "We are police officers, we are not hard killers."

Duterte's threats may be having the desired effect. Hundreds of drug dealers and users have surrendered to police, pledging to reform.

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Alleged drug users and dealers wait to undergo urine tests following their surrender to authorities at Camp Karingal police station in ManilaNoel Celis/AFP
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A man wearing a 'Duterte' wristband is fingerprinted at a police station in Manila after he admitted being a drug userCzar Dancel/Reuters
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Police arrest a man caught with a plastic bag containing solvent in Las Pinas, south of ManilaNoel Celis/AFP
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Alleged drug users and dealers are arrested by police during a night time raid on a suspected drug denDondi Tawatao/Getty
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Police escort a man suspected of selling drugs at a Manila rave at which five people are thought to have died of overdosesNoel Celis/AFP

Armed police have also been rounding up children, drunks and shirtless men in an effort to clean up the streets of Manila. Duterte has said he will impose late-night bans on children walking the streets, alcohol sales and the national passion of karaoke. Adults caught drinking alcohol outdoors are warned – and sometimes forced to do push-ups – and can be fined or detained if they are caught again.

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Social workers and police round up minors out on the streets on Manila after curfewDondi Tawatao/Getty
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Children are temporarily detained at a police station after social workers found them on the streets past the night-time curfewNoel Celis/AFP
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Social workers restrain a woman after her son was detained for violating a curfewNoel Celis/AFP
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A suspected street thief is arrested by a policeman after a brief chase in ManilaDondi Tawatao/Getty
Philippines Duterte drugs
Social workers and police round up minors on the streets of Manila after the night-time curfewDondi Tawatao/Getty Images
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Police detain a man caught drinking and being shirtless on a street in ManilaNoel Celis/AFP
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Men are temporarily detained for drinking or being semi-naked in a public place, in Las PinasNoel Celis/AFP
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Men who were detained for drinking or indecency are made to do 40 push-upsNoel Celis/AFP
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A man who arrested for public disorder offences attempts to do push-ups at a police station in ManilaNoel Celis/AFP
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Homeless people are detained by police on a street in ManilaNoel Celis/AFP
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Men are detained for drinking in public in Las Pinas, south of ManilaNoel Celis/AFP
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A man wearing a 'Duterte' wristband is detained for drinking in publicNoel Celis/AFP
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Young men who violated the 10pm alcohol ban are detained at a police headquarters in ManilaNoel Celis/AFP
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People suspected of committing various crimes and offences are kept in an overcrowded cell in ManilaDondi Tawatao/Getty

Nearly 5,000 suspects have been arrested in anti-drug operations after Duterte was elected, bringing the number of arrests nationwide to nearly 19,000 since January, according to police records.