MANILA, Philippines — The Philippine Senate convened as an impeachment court Monday for the trial of Vice President Sara Duterte over criminal charges, in a time of deep divisions that erupted into an exchange of gunfire last week in the chamber.

The House of Representatives voted overwhelmingly to impeach Duterte last Monday over alleged unexplained wealth, misuse of state funds and a public threat to have the president assassinated if she herself were killed due to their political disputes.

The vice president, who has announced her plan to seek the presidency in 2028, has denied the charges but has refused to answer the allegations in detail. Her lawyers said without elaborating that they “will file the appropriate response … in accordance with the Constitution and applicable rules.”

Her father, former President Rodrigo Duterte, has been detained by the International Criminal Court on charges of crimes against humanity. They stem from anti-drugs crackdowns he ordered while in power that killed thousands of mostly petty suspects.

Ahead of the impeachment trial, 13 of 24 senators led by allies of the Dutertes suddenly wrested the presidency of the Senate last Monday, but it’s still unclear if they can maintain a slim majority.

Several among the 13 senators have been implicated by witnesses in a corruption scandal last year and could face possible arrest if indicted. All those implicated in the flood-control project anomalies have denied any wrongdoing.

The vice president has blamed President Ferdinand Marcos Jr., her former ally and running mate in the 2022 election, for “kidnapping” her ailing father, referring to his arrest and transfer to the international court in The Hague last March.

The escalating disputes between the country’s two top leaders reflect the deep divisions that have long plagued the rambunctious Asian democracy.

One of the senators, Ronald dela Rosa, served as Rodrigo Duterte’s national police chief and enforced his bloody crackdowns on illegal drugs. The ICC has named dela Rosa as a co-conspirator and unsealed a warrant for his arrest last Monday.

That same day, Dela Rosa, who was absent from the Senate for months for fear of arrest, suddenly showed up in the chamber to enable Sen. Alan Peter Cayetano, a key ally of the Dutertes, to gain a slim majority and capture the Senate presidency.

Dela Rosa told reporters he came out of hiding and went to the Senate using Cayetano’s van but was nearly arrested by National Bureau of Investigation agents. He dashed into a stairway and ran to the Senate plenary hall, where Cayetano and other allies placed him under the chamber’s “protective custody.”

A tense standoff between the Senate’s security personnel and government agents positioned in an adjacent government building escalated into an exchange of fire Wednesday night with the Senate personnel firing what their chief, Mao Aplasca, said were warning shots. Marcos appealed to the public to remain calm in a late-night call on national TV.

Cayetano later said that dela Rosa had disappeared from the Senate. Authorities said they were investigating the possibility that the exchange of fire may have been instigated to enable dela Rosa’s escape.