(UPDATE) SILANG, Cavite — President Ferdinand Marcos Jr. on Tuesday said his sister, Sen. Imee Marcos, was entitled to her opinion when she said that the arrest and handover of former president Rodrigo Duterte to the International Criminal Court (ICC) was politically motivated.

"Everyone is entitled to their opinion. I disagree," the president told reporters after attending the graduation rites of the Philippine National Police Academy's Class of 2025.

The senator said the Ombudsman should investigate several Cabinet officials over their involvement in the arrest of Duterte, adding it was a "planned effort" by the Marcos administration.

"A clear pattern begins to arise where major political incidents precede significant statements and actions of the administration cooperating with the ICC," Marcos, head of the Senate Foreign Relations Committee, said on Monday.

"So it's apparent that the final arrest of the former president on March 11 was part of a whole-of-government effort to bring down the Dutertes as early as possible before 2028," she added.

Senator Marcos said she was uncertain whether she would benefit from the apparent "protest vote" from supporters of Duterte who vowed to drop administration-backed candidates.

"I'm not sure because I still carry the Marcos surname," the senator said in Filipino on Tuesday when asked whether she would become a beneficiary of the supposed "zero votes" against the administration's senatorial slate.

Some political observers said the high trust rating of Vice President Sara Duterte in some surveys compared to Marcos' score could be a sign of protest for the alleged role of the government in the arrest of Duterte.

The senator led the inquiry on the arrest of Duterte, now detained in The Hague, awaiting trial for crimes against humanity allegedly committed during his bloody drug war.

She said based on the inquiry's initial findings there was a "concerted effort" to bring the former leader to the ICC due to political reasons.

Asked about her relationship with the president, the reelectionist senator said, "I haven't seen him in ages. I'm sure he's not happy."

Pressed whether the president's senatorial slate would be affected by the protest vote, Senator Marcos said, "I don't know. They (administration) should be the one to assess it. They are the ones who are fond of (commissioning) surveys."

Some of the senator's critics "advised" her to change her surname to Duterte for going against her brother, the president. Sought for her reaction, Senator Marcos said, "I think I don't need to change [my surname] because I follow what my father had taught me."