MANILA (REUTERS) - Philippine President Rodrigo Duterte's daughter would run for president in next year's election and her father's long-time aide, who filed his vice-presidential candidacy, would be her running mate, broadcasting firm ABS-CBN news reported late on Saturday (Oct 2).

Ms Sara Duterte-Carpio is currently mayor of Davao, the Philippines' third-largest city, and filed on Saturday to run for mayor again. She has previously said she would not run for national office next year.

ABS-CBN news based its report on an interview that Mr Duterte had with a broadcast journalist right after he announced that he was retiring from politics while accompanying his closest loyalist, Senator Christopher "Bong" Go, who filed his vice-presidential candidacy.

He was asked: "So is it clear, Sara-Go?" "It is Sara-Go," Mr Duterte said in response.

When asked to confirm what the president said, Ms Duterte-Carpio's spokesman, Mayor Christina Garcia Frasco told Reuters: "The extent of my knowledge is also what was reported in local news. We have no comment on the same."

Mr Go did not immediately respond to a Reuters request for comment.

ABS-CBN news said it obtained permission from the broadcast journalist to use the video showing Mr Duterte outside a hotel in Manila where the registration of candidates was taking place, and that a transcript was also provided.

In the same clip, Mr Duterte was asked when his daughter would file her candidacy for president, he said: "I really do not know. I do not have any idea at all".

Asked if he had given his daughter permission to run for president, he said: "Ah, no, actually we don't talk about politics, ever since we never talk about politics. I would say that it is for the better," Mr Duterte was quoted as saying.

Mr Duterte, 76, said on Saturday he was retiring from politics, a surprise move that fuelled speculation he was clearing the way for a presidential run by his daughter.

He had been expected to run for the No. 2 job, a plan most Filipinos oppose as violating the spirit of the Constitution which sets a one-term limit for the president to stop power being abused.

Ms Duterte-Carpio's mayoral re-election filing, did little to douse speculation she has her eye on the presidency.

Political analysts were sceptical, noting that last-minute changes were still possible, as in 2015 when Mr Duterte entered the presidential election race at the eleventh hour and won by a huge margin, and Ms Duterte-Carpio, they said, could do the same.

Philippine Vice President Leni Robredo will decide this week if she will run for president, her spokesman said on Sunday.

Ms Robredo, a vocal critic of Mr Duterte's controversial drug war, would likely be the only opposition candidate in a crowded field in the May 2022 elections.

Candidates have until Oct 8 to register, but withdrawals and substitutions are allowed until Nov 15, leaving scope for last-minute changes of heart.

The process launches a typically noisy and deadly seven months of campaigning, with the Covid-19 pandemic and the economic downturn caused by lockdowns expected to dampen the party atmosphere.

Surveys have shown Ms Duterte-Carpio, the son and namesake of former dictator Ferdinand Marcos, boxing great Manny Pacquiao and celebrity mayor Francisco Domagoso are the front runners among potential presidential candidates.

Only Mr Pacquiao and Mr Domagoso have announced they are running.

Most of the top candidates have supported Mr Duterte's controversial drug war, and political analysts say vice-president Robredo could struggle to compete if she decides to run.

Filipino voters are willing to elect a female president but they want her to be "feisty", said University of the Philippines political science professor Jean Franco.

"(V-P Robredo is) too good, she's too nice."

Ms Robredo, 56, narrowly won the nation's second top job in 2016, defeating Marcos' son and namesake.

Her victory dealt a blow to the political aspirations of the former dictator's family, including a possible return to the presidential office.