Metro Manila (CNN Philippines, April 25) — Manila Times Managing Editor Felipe Salvosa II has tendered his resignation over the local newspaper's decision to publish the alleged journalists-backed plot to unseat President Rodrigo Duterte.

Salvosa on Thursday said he opposed the publication of the ouster story written by Manila Times chairman emeritus and columnist Dante Ang.

"I didn't agree with the publication of the matrix story," he told CNN Philippines.

The article and matrix published by the newspaper on print and online on Monday claimed there is an ongoing ouster plot against the President, tagging journalists, news-related firms, and lawyers critical of the Duterte administration. It presented a matrix linking these to "Bikoy," the man who claimed Duterte's family and friends are linked to the illegal drug trade.

Salvosa, the coordinator of the Journalism program at the University of Santo Tomas, added that he was also asked by Manila Times to step down because of his strongly-worded social media posts that questioned the accuracy of Manila Times' report.

"A diagram is by no means an evidence of 'destabilization' or an 'ouster plot.' It is a very huge stretch for anyone to accuse PCIJ, Vera Files and Rappler of actively plotting to unseat the President. I know people there and they are not coup plotters," he wrote on his private Twitter page on the day the story was published.

In a statement issued Thursday, Manila Times President and CEO Dante "Klink" Ang II, son of the newspaper's chairman emeritus, said Salvosa "behaved unethically when he posted a statement on social media" without notifying or clarifying with their chairman emeritus.

"The Manila Times has a long-standing open-door policy that allows any employee to contact or visit our Chairman Emeritus, especially on editorial matters. Mr. Salvosa did not object to the story to our Chairman Emeritus, nor did the former managing editor suggest ways of rewriting or handling the piece. He was merely told that copyediting of the story was no longer required as that was done by the editor in chief," Ang said.

The article of the older Ang, who also serves as Duterte's special envoy for international public relations, was heavily backed by Malacañang. Presidential spokesperson Salvador Panelo said the matrix was based on intelligence information gathered by a foreign country, adding these information were obtained through phone conversations.

He said the matrix has been validated. However, gov't forces said there is no clear evidence that will link the journalists to any ouster plot.

The Manila Times stood by its story, as it came from a "credible source," the Office of the President. It added that the article is not a public relations piece and that its chairman emeritus' appointment as special envoy "has no line item or office in the government or remuneration of any kind."

Related: Palace tags journalists, lawyers in alleged ouster plot vs. Duterte; PNP, AFP deny destabilization plan

Tagged journalists Ellen Tordesillas and Maria Ressa, news groups, and lawyers group National Union of Peoples' Lawyers denied the allegation.

Salvosa is not the first one to encounter a sour exit from Manila Times this year. In March, former Senator Kit Tatad claimed he was ordered to stop writing columns for the newspaper following his story that Duterte had a kidney transplant in China.

CNN Philippines Multi-platform Writer Xave Gregorio contributed to this report.