MANILA - Director General Ronald "Bato" Dela Rosa stepped down as chief of the Philippine National Police on Thursday after nearly 2 years at the forefront of the government's war on drugs.

Dela Rosa, who is facing a possible investigation before the International Criminal Court over the drug war killings, said he was retiring from the uniformed service with pride.

“It was something I never dreamed I could reach in my career. It was a challenge I readily accepted with deep humility because of the enormity of the responsibility that comes with the position. It is with great pride I have reached this far in my career,” he said.

Dela Rosa relinquished his post to Director Oscar Albayalde, the former police chief for Metro Manila. Albayalde will serve until November 2019.

A former Davao City police chief, Dela Rosa is among President Rodrigo Duterte's most trusted men. He will be reassigned as chief of the Bureau of Corrections.

At the PNP Dela Rosa faced various crises that tested his leadership.

Among these are the killing of Korean businessman Jee Ick-joo inside the PNP headquarters and the spate of slays of teenagers in what authorities claimed were legitimate anti-drug operation.

Human Rights Watch said Dela Rosa should be held accountable for thousands of killings under the war on drugs, adding the former police chief would leave behind a "sordid human rights record" upon his retirement.

In his assumption speech, Albayalde said he would "impose and breed discipline 24/7" and warned policemen against sleeping on the job.

“I shall commit to continue my low-key but stern kind of leadership. We will focus on imposing strict discipline, reform and internal cleansing, and intensify campaign against criminality and illegal drugs,” he said.

Albayalde said he would continue Dela Rosa’s programs, including anti anti-drug Oplan Double Barrel.