A dispute over courtroom decorum spilled into public view on Saturday after Senator-judge Panfilo Lacson said the spokesperson of the Senate impeachment court had overstepped his role by publicly reminding lawmakers to avoid statements that could compromise the trial of Vice President Sara Duterte.

Impeachment court spokesperson Reginald Tongol on Friday invoked Rule 18 of the Senate Rules of Procedure on Impeachment Trials after a Facebook post by Senator Robinhood Padilla defending Duterte prompted questions about whether some senator-judges were risking the appearance of bias.

"With due respect to Atty. Tongol, he is the spokesperson of the Impeachment Court and speaks on behalf of the senator-judges. He should not make it appear he is cautioning or admonishing us," Lacson said in a radio interview.

Tongol had told reporters that Rule 18 of the Senate Rules of Procedure on Impeachment Trials prohibits senator-judges from making public statements on the merits of the case while proceedings are ongoing. 

While he declined to say whether Padilla had violated the rule, Tongol said it would ultimately be up to the impeachment court to determine whether any senator's actions ran afoul of the rules. He stressed that public comments could invite questions about the court's impartiality. 

Lacson said Tongol should not be publicly policing the conduct of the very lawmakers he represents. Instead, he said, questions over a senator-judge's conduct should be settled behind closed doors.

"If there are indiscretions committed by a senator-judge, it is best to take it up in an all senator-judges' caucus, instead of lecturing in public or during the trial," he said.

Lacson singled out Tongol's remarks on Padilla's Facebook activity, calling them "uncalled for."

"It is not in his space to call the attention of senator-judges to adhere to Rule 18 of the Rules of Procedure on Impeachment Trials, even sounding like he was admonishing Sen. Padilla for his FB comments," he said.

Padilla drew criticism this week after posting excerpts of the impeachment proceedings on Facebook along with commentary widely seen as supportive of Duterte's defense.

Padilla, one of Duterte's most outspoken allies in the Senate, has long opposed efforts to remove the vice president from office. 

Even before the trial began, he publicly declared he would vote to acquit Duterte and has repeatedly defended her during the proceedings, prompting renewed debate over whether some senator-judges should inhibit themselves from the case.

Despite criticizing Tongol, Lacson agreed that senator-judges themselves have an obligation to exercise restraint.

"As senator-judges, we should be responsible enough and conscious of our statements because we are senator-judges. We cannot make statements in interviews or during the trial that may project leaning toward the prosecution or the defense," he said.

Lacson also said senator-judges may hold another caucus next week to tackle pending motions, including Senator Alan Peter Cayetano's proposal asking the court to coordinate with the Sandiganbayan so detained senators, among them Jinggoy Estrada, could attend the proceedings in person.

The Senate impeachment court will resume its hearings on Monday after prosecutors began presenting evidence against Duterte on grave threats, the 4th impeachment article.