Senator Rodante Marcoleta was arrested Monday and charged under Philippine anti-corruption statutes, becoming the latest member of the upper legislative chamber to face accusations of large-scale graft in recent weeks. Marcoleta denies any wrongdoing.

The 72-year-old lawyer was taken into police custody at the Sandiganbayan special anti-graft court in suburban Quezon City. He faces a charge of plunder, a legal term in the Philippines for illegally amassing vast sums of money through criminal acts, which does not allow for bail.

Marcoleta belongs to the Iglesia ni Cristo (Church of Christ), a religious group whose members organized a three-day rally of more than 15,000 people to protest the charges and Marcoleta's impending arrest. The demonstration caused significant traffic congestion in metropolitan Manila.

President Ferdinand Marcos Jr. canceled two official engagements outside his office on Tuesday due to concerns over the protest by the influential religious organization, known for its capacity to mobilize large gatherings.

The Office of the Ombudsman, a specialized anti-graft prosecutor, filed the plunder charge against Marcoleta last week. The accusation states he received 75 million pesos ($1.2 million) in what were presented as campaign contributions from three supporters, which he failed to declare in his assets statement as legally required. Two of these donors, including former House of Representatives member Mike Defensor, were also arrested Monday, according to Interior Secretary Jonvic Remulla.

This arrest follows that of Senator Jinggoy Estrada, a political ally of Marcoleta, who was detained early last month on a non-bailable plunder charge. Estrada is accused of allegedly pocketing a substantial kickback from a flood-control project. The 63-year-old senator has vehemently denied the allegations, which stem from claims by a former government public works engineer that Estrada received over 570 million pesos ($9.3 million) in kickbacks.

Both Marcoleta and Estrada were supporters of former President Rodrigo Duterte and his daughter, Vice President Sara Duterte. Meanwhile, the 24-member Senate was scheduled to begin impeachment proceedings against Sara Duterte, who was impeached by the House of Representatives in May. She denies committing alleged high crimes, including accumulating undeclared wealth and making public threats against the president. A third senator and Duterte ally, Ronald dela Rosa, has reportedly gone into hiding after the International Criminal Court issued an arrest warrant for him in connection with alleged crimes against humanity related to the previous administration's anti-drug campaign. Former President Duterte himself was arrested last year by the ICC and is scheduled to face trial in the Netherlands on November 30.