House prosecutors on Thursday rejected the defense's claim that Vice President Sara Duterte's controversial threats were merely "conditional," arguing that such statements may still constitute a crime under Philippine law.

Speaking during a press conference after the first week of the Senate impeachment trial, members of the prosecution panel challenged the defense's reliance on an alleged plot dubbed "Oplan Romanov" to justify Duterte's remarks.

House private prosecutor Jay Tolosa said the defense failed to present evidence proving the alleged conspiracy against the Vice President and her family.

"This Oplan Romanoff in this trial, we only heard about it in the statement of the defense counsel. It is clear that there is not an ounce of evidence that they can lay out to prove it in any way," Tolosa said.

"It remains an allegation. And at the end of the day, it seems that by raising this matter, they're trying to justify the threats."

Tolosa added that even if such a plot existed, it would not justify publicly threatening President Ferdinand Marcos Jr., First Lady Liza Araneta-Marcos, and former House Speaker Martin Romualdez.

House Deputy Speaker Paolo Ortega V likewise said the alleged existence of "Oplan Romanoff" does not diminish the seriousness of Duterte's statements.

"Like I said, this is not a joke. It's a grave crime. Regardless of what threat it is. Saying it's a conditional threat is just an excuse of people that state grave threats," Ortega said.

"That's a threat to the highest official of the land."

He added that it was unprecedented for the country's second-highest official to publicly declare that she had devised a way to kill the President and other top government officials.

Meanwhile, House public prosecutor Ysabel Maria Zamora said the characterization of the threat as "conditional" or "absolute" has no bearing under criminal law.

"You know, it might not matter if the threat was conditional or absolute. In any case, criminal law does not identify a conditional threat. As long as it is a threat, it's a threat," Zamora said.