MANILA — The Roman Catholic Church has offered to protect police officers who want to come forward and testify about their participation in President Rodrigo Duterte’s bloody war on drugs, a prominent archbishop said on Monday.

The protection offer could escalate an emerging clash between the church and the government.

More than 80 percent of the Philippine population is Catholic, and the church has long been a political force in the country. Since the killing of a 17-year-old boy by police officers in August, the church has led protests demanding accountability for the victims of Mr. Duterte’s antidrug campaign, which has left thousands dead at the hands of police officers or vigilantes.

In a pastoral letter, Archbishop Socrates B. Villegas, president of the Catholic bishops conference in the Philippines, said officers had come forward with misgivings about their role in the war on drugs. “They have expressed their desire to come out in the open about their participation in extrajudicial killings and summary executions,” he wrote. “Their consciences are troubling them.”