The Philippine National Police will continue its campaign against illegal drugs despite rising fatalities even as it gears up to appear before a two-day Senate inquiry next week.

Director General Roland de la Rosa said in a press conference on Tuesday the national police are “determined to finish this ( campaign against illegal drugs) in six months. I don’t care whatever investigation would come on the way.”

“I will continue to motivate my men to exploit the momentum. The momentum is on our side. We don't have to slow down. We will continue the fight," the chief of the national police added.

Dela Rosa and other police officials will appear in a Senate inquiry on extrajudicial killings on August 22 and 23.

He vowed to be truthful in their answers and hoped the lawmakers will treat them with respect.

"These senators are honorable people. I think they will not disrespect us," he said. "In every action there is a corresponding reaction. If we are disrespected we may probably lose our cool," said de la Rosa.

Most alleged summary executions of drug suspects were done by illegal drug syndicates who are in a war against each other, said de la Rosa.

And these executions were not done by vigilantes perceived to be supporting President Rodrigo Duterte's anti-drug campaign.

"You will be surprised. These were not done by vigilantes. These alleged vigilante killings that came out are instead syndicated killings," Dela Rosa said.

Dela Rosa's disclosure is based on investigation by the police Directorate for Investigative and Detective Management on summary killings which Senator Panfilo Lacson called on the police to address unless they are tolerating these.

"We will release the data and facts on who are killing each other," said Dela Rosa. “We are just sorting this out because we scientific evidence leading to that conclusion."

He revealed in previous interviews convicted drug lords at New Bilibid Prisons have ordered the killings of their drug peddlers who could no longer remit earnings from drug transactions.

At least 612 drug suspects were killed in what police say are legitimate operations. But, Lacson said there are about 618 people with alleged links to the illegal drug trade slain by vigilantes since July 1. Emmanuel Tupas