President Rodrigo Duterte on Tuesday distanced himself from alleged sightings of his in-laws in the Bureau of Customs offices.

"If any of my children, kung yan ang pumasok, may hiningi na illegal for graft and corruption, I am ready to step down as president," Duterte said in a speech delivered before new government appointees.

"Nilimit ko sa mga anak ko kasi wala akong control sa ibang tao. I can only answer for my sons and daughters," he added.

The president's statement came after Manases Carpio, his son-in-law, and Lovely Sumera, his son Paolo's first wife, were reportedly seen in different Customs offices, fueling allegations of corruption.

SARA'S HUSBAND

Resigned Customs Intelligence chief Neil Estrella earlier told lawmakers that he once saw Carpio, husband of Davao City Mayor Sara Duterte, leaving Customs Commissioner Nicanor Faeldon's office.

Carpio, in a statement, explained that he was in the Customs office to represent several clients.

"I represent many clients who have transactions with the Bureau of Customs. It is my job as a lawyer to appear before government agencies for and on behalf of my principals," Carpio said in a statement.

The president backed his son-in-law's claims and said that Carpio has long been lawyering for cigarette giant Mighty Corporation that allegedly underdeclared its goods earlier this year.

"Ito namang kay Mans, I do not apologize for him because he's a lawyer. Lawyering, no one can question us. It's part of our vocation as a lawyer," Duterte said.

PAOLO'S EX-WIFE

Sumera's appearance in some Customs offices also raised suspicions about the presidential son's possible involvement in sketchy Customs deals.

Senator Antonio Trillanes IV earlier alleged that the vice mayor was behind the "Davao Group" that supposedly received grease money from brokers who smuggled contraband into the country.

"There seems to be an allegation that a daughter-in-law of mine visited customs. She is not a Duterte, she is a Sumera," the president said.

"I haven't seen her in the last 10 years. Unang asawa siya ni Pulong," he added.

Duterte said Paolo and his estranged wife eloped when the vice mayor was still 18 years old.

"That was one of the sad moments of my life because I never saw him for 5 years until malaman ko na meron na akong apo so I sought him out. The girl married again, she's a Sumera now," Duterte said.

The president said he does not consider Sumera as part of his extended family.

"I do not have a daughter by the name of Lovely Duterte. Ang daughter in law ko is si January," he said, referring to Paolo's current wife.

The president called on government officials not to give his 3 children favors should they come knocking on their office doors.

"Aside from me stepping down from the presidency, cases should be filed against my children should they engage in graft and corruption, the Duterte patriarch said.

"I-demanda na ninyo. Wala akong pakealam diyan," he said.