Manila, Mar 11 (IANS): Three Philippines priests said on Monday that they received death threats after criticizing President Rodrigo Duterte for his violent war on drugs.

The three Catholic priests -- Albert Alejo, Flavie Villanueva and Robert Reyes -- held a press conference in Manila to reveal the threats, two weeks after the Bishop of Caloocan Pablo Virgilio David, one of the Philippines clergymen most critical of Duterte, confirmed receiving similar threats.

Reyes said the threats were a result of the three priests standing firm in condemning the President's war against drugs as an "inhuman campaign" which affected the poorest people in the country, Efe news reported.

During Monday's press conference, the priests showed copies of the threats, issued in Tagalog, which they had received on their mobile phones and said they were making them public because they were worried for their personal safety.

Alejo appealed to the "brains behind the threats", or people who encouraged the murders, and urged them to stop and abandon "this way of life".

Priest Villanueva showed a number of video clips filmed outside his house -- situated inside a care centre for the poor in Manila -- in which a masked man can be seen watching the building for many days.

The footage also identified a white van, which left the surroundings of the building at the same time as the masked man.

The revelation of the threats came amid heightened tension between Duterte and the hierarchy of the influential Catholic Church of the Philippines.

In Philippines, where around 85 per cent of the population is Catholic, the bishops and Duterte have traded war of words on various occasions before, especially on the issue of the drug war.