MANILA - The only son and namesake of the late dictator Ferdinand Marcos, who narrowly lost the vice-presidential race, said Saturday he was robbed of around three million votes and accused outgoing President Benigno Aquino III's government of masterminding alleged vote-rigging operations.

Senator Ferdinand "Bongbong" Marcos Jr. said he would file a protest to contest the victory of Vice President-elect Leni Robredo by the end of the month. He said he has gathered evidence of fraud both from witnesses and "experts" who flagged irregularities in the automated system.

"Talagang maliwanag na maliwanag sa taumbayan na napakalawak at napakawalanghiya ang pangbabastos at pangwawalanghiya sa boses ng taumbayan," Marcos told reporters.

"Iisa lang pwede gumawa niyan, administration. We have to lay that at the door of the administration," he said.

He refused to say who was specifically behind the alleged cheating. "We're not yet there but we will slowly be able to... Lalabas at lalabas ang mga pangalan na yan. Kung may nangyari, may nag-authorize niyan," he said.

Marcos' defeat effectively derailed the family's resurgence in national politics, analysts have said. Winning the vice-presidential race was seen as a stepping stone for a possible presidential run in 2022.

Marcos' six-year term in the Senate will end on June 30. His mother, flamboyant former first lady Imelda Marcos, and elder sister, Imee Marcos, were elected congresswoman and governor respectively of Ilocos Norte province, the family's bailiwick.

The senator said he has received reports all vice presidential candidates, except Robredo, got zero votes in some areas, even as he secured the endorsement of the Christian sect Iglesia ni Cristo (INC).

"That is not highly improbable that is in fact impossible," he said.