Democrats subpoena Pentagon for Ukraine documents

House Democrats issued subpoenas to the Pentagon and the White House budget office on Monday, as they build their impeachment case against President Donald Trump, who on Monday railed against the whistleblower who touched off the investigation and took aim at a second one, saying: "Bring in another Whistleblower from the bench!"

Lawyers said a second whistleblower, who claims to have "firsthand knowledge" of Trump's actions, had come forward to substantiate a complaint from an unnamed U.S. government official, who raised concerns over allegations Trump pressured Ukraine's president to investigate his political rival, Former Vice President Joe Biden.

House officials on Monday said Deputy Secretary of State George Kent, who was scheduled to be interviewed behind closed doors on Monday, will not testify and will be rescheduled.

Gordon Sondland, the U.S. ambassador to the European Union who was involved in efforts to get Ukraine to open the investigations, is scheduled to testify on Tuesday.

Diplomatic text messages released last week show Sondland seeking to downplay the concerns the U.S. was withholding $400 million in aid in order to secure Ukraine's cooperation.

Democratic lawmakers have also demanded documents from the White House, which could formally tell House Speaker Nancy Pelosi as early as Monday that it will ignore those demands until the House holds a vote to formally approve the impeachment probe.

(SOUND BITE) (ENGLISH) U.S. REPRESENTATIVE JIM HIMES, SAYING:

"There's no question in my mind that she would have the votes."

While Pelosi says a vote is not needed, Democrats say she would prevail if one were held.

In a set of angry, late-night tweets on Sunday, Trump lashed out at Pelosi, saying she could be guilty of treason, an attack he previously made against House Intelligence Committee Chairman Adam Schiff.

Trump has denied wrongdoing and continues to assail the impeachment investigation.