Democrats must approve. any requests submitted by Republicans and they expect to deny requests for Hunter Biden and the whistleblower to appear.
CNN reached out to attorneys for the whistleblower and Hunter Biden for comment.
In a letter, California Rep. Devin Nunes, the top Republican on the House Intelligence Committee, read what he called a "sham impeachment process." "Nunes writes that Republicans have called witnesses to testify in an open setting to" provide transparency to your indefensible and unfair process. "
House Democrats are advancing their investigation led by Trump wants Ukraine to investigate Joe Biden, son of former vice-president and the 2016 presidential election to help the President politically and the White House take steps to cover it. Trump refuses to do anything wrong.  Trump dismisses a false accusation that Vice President Biden improperly tried to help his son by pressing the Ukrainian government to fire the country's prosecutor Hunter Biden serves on the board of the Ukrainian natural gas company at that time.
No evidence of wrongdoing by Joe or Hunter Biden in Ukraine.
Biden presidential campaign declined to comment a CNN Saturday on request. for the son of the former vice president to testify. Joe Biden was asked Friday in New Hampshire if he himself would testify in an impeachment Senate hearing when asked – even though Republicans had not made that request.
"Let's focus on the problem, here," Biden said. "The question is, does the President of the United States violate the Constitution … And does he earn from his office." Trump again called for him to file his tax returns.
It consolidated efforts to strengthen a strategic strategic alliance after Trump enlisted his own personal lawyer, Rudy Giuliani, to work outside normal diplomatic channels in an apparent effort to oust his reelection Chances are.
CNN's Jeremy Herb, Manu Raju and Marshall Cohen contributed to this report.