The Philippines independent human rights watchdog has said it will investigate claims by President Rodrigo Duterte that he personally killed drug suspects while mayor of Davao.
The Commission on Human Rights will also examine reports that so-called death squads killed several hundred people in the southern city.
Mr Duterte confirmed to the BBC last week that he shot dead three men.
Since being elected in May, he has waged a brutal anti-drugs crackdown.
Critics say he has encouraged police, vigilantes and mercenaries to shoot suspected drug dealers and users on sight. Nearly 6,000 people are said to have been killed.
Mr Duterte was mayor of Davao for two decades, during which time he earned a reputation for harshly suppressing crime and was accused of sponsoring death squads.
On Tuesday, UN High Commissioner for Human Rights Zeid Ra’ad al-Hussein said Mr Duterte’s claims “clearly constitute murder” and he called on authorities to investigate.
Jose Gascon, who heads the Philippines Commission on Human Rights, said on Wednesday a team of investigators would look into the matter.
“Law enforcement agencies… must investigate as a matter of course any information that suggests that a crime may have been committed with the view to ensuring that perpetrators are ultimately held accountable should the evidence warrant it,” Mr Gascon said.
During Mr Duterte’s time as mayor of Davao, the commission investigated claims that he ran death squads that targeted petty criminals, but no criminal charges were filed.
Mr Gascon said the inquiry would be “reconstituted… to look into the new revelations and public admissions that may shed light on our previous findings”.
Earlier this month, Mr Duterte told a group of business leaders that in Davao “I used to do it [kill] personally. Just to show to the guys [police] that if I can do it, why can’t you”.
His spokesman later dismissed the comments as “tough talk” and denied that Mr Duterte had killed anyone.
But speaking to the BBC hours later, Mr Duterte said: “I killed about three of them… I don’t know how many bullets from my gun went inside their bodies. It happened and I cannot lie about it.”
One of the president’s most strident critics in the Philippines, Senator Leila de Lima, has said his admission could be grounds for impeachment.
But on Wednesday, the government filed criminal charges against Ms de Lima, accusing her of trying to sabotage a congressional investigation into her alleged involvement in the drugs trade. She strongly denies any wrongdoing.
Earlier this week, Ms de Lima told the BBC that she feared for her life, but will not be silenced.
Mr Duterte has dismissed concerns over his anti-drugs policies.