Former White House Deputy Chief of Staff Rick Dearborn and former White House Staff Secretary Rob Porter were subpoenaed by the House Judiciary Committee to appear at the hearing on possible obstruction of justice by Trump.
The panel, which hopes to decide whether to recommend Trump's impeachment to the full House by year-end, will meet on Thursday to consider a resolution that Democratic panel aides said would better align the inquiry with formal ones of the past.
Attorney General Jeff Sessions says he has fired former FBI Deputy Director Andrew McCabe, a longtime and frequent target of President Donald Trump's anger, just two days before his scheduled retirement date.
The public testimony Tuesday before the Senate intelligence committee should yield Sessions' most extensive comments to date on questions that have dogged his entire tenure as attorney general and that led him three months ago to step aside from the Russia probe.
The intense attention being given to the new U.S. attorney general's meetings with Russia's ambassador could obstruct improved Washington-Moscow relations, the spokesman for Russian President Vladimir Putin said Thursday.