"I was one of those who started it," he said. "We implemented the personal instructions of (then-Mayor) Duterte to us. All of the killings we did in Davao city, whether we buried or threw them out to sea."
Duterte, though a spokesman, dismissed the allegations as "nothing but vicious politics."
"The Commission of Human Rights, the Office of the Ombudsman, the Senate Committee on Justice already cleared the President of extrajudicial killing and his involvement in the Davao Death Squad," Presidential Communications Secretary Martin Andanar said in a statement.
Retired Davao Senior Superintendent Dionisio Abude during the same inquiry denied the existence of death squads.
At the news conference, Lascanas said Monday he was confessing in an effort "to follow God's will ... and love for my country and for my own conscience." The event was organized by opposition Senator Antonio Trillanes IV.
Allegations of mosque bombings, killings
Lascanas said the squad had undertaken many killings and other criminal actions, either at the orders of Duterte or his associates. Duterte served as mayor of Davao for 10 years starting in 1988, then again from 2001 to 2010, and from 2013 to 2016.
Lascanas said the squad had been ordered by Duterte personally to bomb Davao mosques in 1993 in retaliation for the bombing of San Pedro Cathedral.
"It's true, I was one of those who received personal orders from Mayor Duterte," Lascanas said.
Lascanas also claimed he was among a group of people ordered by a Duterte associate to kill radio journalist Jun Pala. He said they were told Duterte was "very angry" at Pala.
After Pala escaped twice, Lascanas alleged he met Duterte briefly at a mall in Davao. He said Duterte told him not to rush the job.
"He told me, 'Take time,'" Lascanas said. "Jun Pala was killed. Two days later, we were given by Mayor Rody Duterte ... an amount of 3 million pesos."
Pala was killed in 2003. The alleged payment would be worth about $80,000 today.
Pala's murder remains unsolved.
Over the course of his time in the Davao squad, Lascanas said he was usually paid between 20,000 to 100,000 pesos per kill. He said he received an allowance from Duterte's office when he was mayor.
Lascanas also claimed he had killed two of his own brothers while working in the death squad, out of "blind loyalty" to Duterte.
"They were involved in illegal drugs," he said. "It was a very painful decision for me. No one knew about what I did but me."
Second hitman to speak out
During his appearance at the now-closed Senate inquiry into extrajudicial killings, Matobato claimed more than 1,000 people were killed by the death squad while Duterte was mayor.
He said it had begun as a smaller squad of about seven people but grew after 1993 to include police members.
More than 7,000 people have died since Duterte unleashed his war on drugs last June, according to police figures.