Philippine President Rodrigo Duterte's 6th State of the Nation Address (SONA) | IMG SOURCE: Reuters

MANILA, Philippines -- President Rodrigo Duterte has agreed to be the ruling political party's vice presidential candidate in next year's elections, the PDP-Laban party said on Tuesday, solidifying his bid to stay in a top government post once his term ends next year.

Duterte agreed to run due to "popular calls" within the PDP-Laban for him to seek the second-highest post, the party said in a statement Tuesday. The ruling party, which will convene next month, is also seeking continuity in the administration's economic and anti-illegal drugs agenda.

The PDP-Laban party made the announcement ahead of a national assembly on Sept. 8 where it is also expected to endorse Duterte's aide and incumbent senator Christopher "Bong" Go to be its presidential candidate in the 2022 polls.

Duterte is making "the sacrifice" and heeding "the clamour of the people," Karlo Nograles, executive vice president of the ruling PDP-Laban party, said in a statement.

According to the Philippine constitution, the president is limited to one six-year term and Duterte's term is due to end by June next year. His vice presidential run is seen by political observers as a backdoor to the presidency however.

Nograles said the move would "guarantee continuity of the administration's programmes during the past five years," including those meant to address illegal drugs.

Duterte's critics believe he could be making a play for retaining power through the number two post, by taking over as president in the event ally Go wins and then resigns.

Duterte, who has portrayed himself as a reluctant president with no desire for power, has on several occasions said he wanted Go to be his successor. His endorsement in 2019 helped Go to become a senator, a post he carries out alongside his duties as Duterte's personal aide.

Go has been the 76-year-old's closest aide since the late 1990s, when Duterte was a congressman representing Davao City in the country's south.

"I am still not interested (in the presidency)," Go, who chairs the senate committee on health, told Reuters. "Vaccines first, before politics," he added.

Duterte has said he wants to shield Sought for comment, Go said he would rather focus on addressing the pandemic. "I am still not interested (in the presidency)," said Go, who chairs the senate committee on health. "Vaccines first before politics" himself from possible legal action when he leaves office.

That may include a possible investigation by the International Criminal Court for crimes against humanity. The ICC's prosecutor has sought the go-ahead to launch a formal investigation into the killings committed during Duterte's war on drugs.