At least two bishops and three priests critical of the Philippine government have received death threats in the past month following President Rodrigo Duterte's denunciations of church leaders, including a call for the killing of bishops.

The threats are unprecedented in Asia's largest Catholic country, and underline how Duterte's insults against the church can have real-world consequences, The Washington Post reported.

Three priests have been killed from December 2017 to June 2018, with the deaths having one unpunished.

Jesuit priest Albert Alejo, Divine Word missionary priest Flavie Villanueva, and diocesan priest Robert Reyes told a media briefing on March 11 that they are in fear of their lives, ucanews.com reported.

"We're not safe," said Father Reyes, known as the "running priest" for his fondness of long-distance runs to draw attention to human rights issues.

"We are afraid," said Father Alejo, noting that they were "fortunate" to have received threats unlike the "thousands of others killed without warning."

The Philippines government has admitted that 5,176 "drug personalities" have died in 119,841 anti-narcotics operations since July 1, 2016, when President Rodrigo Duterte came to power.

Authorities, however, said all were killed while resisting arrest or attacking arresting officers.

Human rights groups claim more than 20,000 drug-related killings have been classified by police as "deaths under investigation."

The threats against the three priests come soon after Bishop Pablo Virgilio David of Kalookan, the diocese where most drug-related killings have occurred, and Archbishop Socrates Villegas of Lingayen-Dagupan, a vocal critic of Duterte, announced that they had also received death threats.

The priests said Duterte's invectives against the Philippine church were an attempt to undermine what is possibly the biggest and most powerful institution critical of his drug war, said The Washington Post.

Reyes denounced what he said was a "systematic and deliberate and purposeful tactic to divide the church, which is now leaping on its moral duty to fight against injustice and extrajudicial killings."

The threatening messages cannot be directly linked to the Duterte administration, but the priests said they believe they were at least inspired by the president's rhetoric.

"In December Duterte said, "These bishops of yours, kill them....They're good-for-nothing fools. All they do is criticize."

His spokesman later dismissed the statement as "hyperbole."

Duterte has also claimed that he was sexually assaulted by a priest as a student, The Washington Post reported.