MANILA - President Rodrigo Duterte on Wednesday said he was willing to step down if anyone among his children is proven to be involved in corrupt practices.

Duterte made this vow once again after the name of his son, Davao City Vice Mayor Paolo Duterte, came up at a House of Representatives hearing into the P6.4-billion illegal drug shipment from China that was smuggled through the port of Manila.

The controversy triggered separate investigations at the House and the Senate.

“Corruption is really one [thing] I don’t like. Pati 'yung anak ko ngayon sinasali sa Customs (controversy),” Duterte said in a speech at the Philippine Development Forum: Sulong Pilipinas 2017 Wednesday.

“I told you before and I’m telling you now again, kung sino sa mga anak ko ma-involve sa corruption, I will immediately resign,” said the President, who has pursued a fierce campaign against corruption and has fired his own appointees over such allegations.

At a House hearing on Monday, customs broker Mark Taguba mentioned a "Tita Nani" who he supposedly met through a "Davao Group" when lawmakers asked him to name personalities involved in bribery activities at the Bureau of Customs (BOC).

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This group, Taguba said, is allegedly backed by a "Vice Mayor." However, he said, those involved could have just resorted to namedropping an official to seal a deal.

In a statement released Tuesday, the President’s son, who felt alluded to, emphasized that Taguba himself admitted that the testimony against him was based on hearsay.

"Taguba admitted that his testimony against me was based entirely on rumors. Why would we entertain or believe a hearsay? One does not dignify lies with a response," he said.