MANILA — Vice President Leni Robredo will make an "important announcement" on Oct. 7, a day before the filing of candidacies for the 2022 elections closes, her office said on Tuesday.

Robredo, a vocal critic of some of President Rodrigo Duterte's policies, would likely be the only opposition candidate in a crowded field in the May 2022 elections. Duterte over the weekend declared he was retiring from politics.

Robredo, who has not yet accepted opposition coalition 1Sambayan's nomination as presidential contender, will make her announcement at 11 a.m. Thursday, said her spokesperson Barry Gutierrez.

VP Leni will make an important announcement this Thursday, Oct 7, at 11 am. Please stay tuned.

— Barry Gutierrez (@barrygutierrez3) October 5, 2021

It comes a day after former Sen. Ferdinand "Bongbong" Marcos, Jr., whom she defeated in the 2016 vice presidential race, declared his bid for the presidency in 2022. His camp did not say when he will formally file his candidacy.

• Bongbong Marcos declares 2022 run for president

Robredo said last Sept. 17 that she was ready to face Marcos or any other opponent in the 2022 elections, even as he had yet then to firm up her plans for next year.

"Kung ano iyong mapili ng unity ticket, tatakbo ako. Kung ako iyon. Kung one-on-one na Bongbong Marcos, lalaban ako kahit dehado," Robredo said then.

(Whatever the unity ticket chooses, I will run. If that's me. If it's a one-on-one against Bongbong Marcos, I will fight.)

• Robredo says ready to face Marcos, any rival in 2022 elections

Duterte, who is constitutionally barred from seeking a second term, had declared in August he would run for the vice presidency. But in a surprise announcement Saturday, he said he would retire -- which was met with deep skepticism among analysts.

• 'Retiring' Duterte: 'Time for a new set of leaders'
• Doubting Duterte retirement? Wait for candidacy, substitution deadlines

Duterte made a similar announcement in September 2015, saying he "will retire from public life for good", only to declare his presidential bid 2 months later.

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The President has not named a successor, but indicated his daughter Davao City Mayor Sara Duterte-Carpio will run alongside his longtime aide Sen. Christopher Go.

A broadcaster asked him Saturday if it was "clear it will be Sara-Go". Duterte responded: "It's Sara-Go."

• Duterte: Sara to run for president, with Go as her VP
• Bong Go files COC for vice president

Duterte-Carpio has said she would not run if Duterte sought the vice presidency and registered her bid for reelection as mayor last week. Her father's retirement may pave the way for her to contest the country's highest office.

Aside from Marcos, other contenders to lead the country of at least 109 million include boxing great Sen. Manny Pacquiao, former actor and incumbent Manila Mayor Isko Moreno Domagoso, and Sen. Panfilo Lacson.

Most of the top candidates have supported Duterte's controversial drug war, and political analysts say 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.

"(VP Robredo is) too good, she's too nice."

In endorsing Robredo as 1Sambayan's presidential candidate, retired Senior Associate Justice Antonio Carpio, a convener of the coalition, said, "We ask the Filipino people to join 1Sambayan in supporting VP Leni as the next President who will lead us in healing our nation, reviving our economy, generating employment, eliminating hunger, ending the wanton killing of fellow Filipinos, eradicating graft and corruption, defending our sovereignty and sovereign rights, strengthening our democratic institutions, upholding our civil liberties and restoring our pride and dignity as a people."

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

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

The Philippine election season kicked off last Friday as celebrities and political scions flocked to the offices of the elections commission to file their nominations.

The process launches a typically noisy and deadly 7 months of campaigning for more than 18,000 positions, with the COVID-19 pandemic and the economic downturn caused by lockdowns expected to dampen the atmosphere.

— With a report from Agence France-Presse