MANILA - Senator Antonio Trillanes IV questioned Davao Vice Mayor Paolo Duterte's "delicadeza" when the presidential son announced his resignation on Monday.

In a statement released Christmas Day, Trillanes called Duterte's resignation out of delicadeza "pure BS," considering that he had a public squabble with his own daughter.

"Pinatulan nga niya anak niya publicly sa Facebook, tapos delicadeza? Besides, he has already been cleared months ago by Gordon's committee de abswelto. So that's pure BS," he said.

BASAHIN: Sen. Antonio Trillanes, hindi naniniwalang delicadeza ang dahilan ng pagbibitiw ni Davao city Vice Mayor Paolo Duterte pic.twitter.com/gytqSkrjzX

— Zandro Ochona (@ZandroDZMM) December 25, 2017

The senator was referring to social media word war between Duterte and his daughter, Isabelle, where they swapped curses and accusations.

• READ: Paolo Duterte spews vitriol at daughter's online rant

In his resignation announcement, Duterte said it's time for him to honor the principle of delicadeza which he learned from their parents.

"When I was growing up my parents never failed to remind us of the value of the time honored principle of delicadeza and this is one of those instances in my life that I need to protect my honor and that of my children... I hereby tender my resignation as Vice Mayor of Davao City effective today December 25, 2017," he said.

Trillanes and Duterte had their share of word war when the son of President Rodrigo Duterte faced a Senate probe on a billion-peso drug shipment that slipped past the Bureau of Customs.

The senator accused the young Duterte of being a member of the Chinese triad and the alleged "Davao Group" which is involved in smuggling.

Duterte has repeatedly denied these allegations. The President's eldest son has already said before that he will retire from politics in 2019. -- report from Zandro Ochona, ABS-CBN News