Democrats in the U.S. House of Representatives have issued subpoenas to the Pentagon and White House budget office as part of their impeachment inquiry into President Donald Trump, requesting documents relating to Trump's decision to withhold military aid to Ukraine.

Three Democratic committees Monday demanded Defense Secretary Mark Esper, and Office and Budget and Management Acting Director Russell Vought turn over the documents by Oct.15. Democrats are investigating Trump's actions of pressing Ukraine to investigate his Democratic rival Joe Biden and his son, Hunter. Part of the investigation includes examining whether or not Trump's decision to withhold military aid to Ukraine was tied to his request for a Ukrainian investigation into the Bidens.

The development follows news on Sunday that a second U.S. intelligence whistleblower has come forward with a complaint about the actions of the Trump administration.

Attorney Mark Zaid, who represents both whistleblowers, confirmed the news to VOA.

The complaint filed by the first whistleblower is what sparked the impeachment investigation. The complaint alleges Trump used "the power of his office to solicit interference from a foreign country in the 2020 election," and cited a phone call between Trump and Ukrainian President Volodymyr Zelenskiy to look into alleged corruption in Ukraine by the former vice president and his son.

Trump has strongly denied any wrongdoing. He has repeatedly termed the call with Zelenskiy as "perfect," while attacking his critics as "traitors" and alleging a "coup" is in the works to remove him from office.

Also Sunday, Trump accused House Speaker Nancy Pelosi of being guilty of "High Crimes and Misdemeanors, and even Treason," crimes that are the same level of offense as those the U.S. Constitution cites as the threshold for removing a president from office.

Trump's tweet late Sunday also reiterated his criticism of Congressman Adam Schiff, chairman of the House Intelligence Committee and the Democrat whom Pelosi has tasked with leading the impeachment inquiry.

Trump took offense to the way Schiff described a phone call between him and the leader of Ukraine. On Sunday, he said Pelosi knew of Schiff's "lies and massive frauds."

Schiff said at a committee hearing that the transcript of Trump's call with the Ukrainian president reads like "a classic organized crime shakedown," and that Schiff's own version of the conversation was meant to be a parody.

The impeachment inquiry is moving forward this week with the House Intelligence, Foreign Affairs and Oversight committees set to hear testimony from several important figures. On Tuesday, they are scheduled to hear from U.S. Ambassador to the European Union Gordon Sondland. On Friday, Marie Yovanovitch, who was recalled from her post as the U.S. ambassador to Ukraine, is scheduled to testify.

The House committees are also waiting for answers to their subpoenas for documents from the State Department, White House and Trump's personal lawyer, Rudy Giuliani.

Trump reacted Sunday to news of a second whistleblower with a flurry of tweets, repeating unproven claims of corruption by the Bidens.

"The Biden family was PAID OFF, pure and simple. The fake news must stop making excuses for something that is totally inexcusable," Trump said.

He has alleged that when Joe Biden was vice president, he threatened to hold up loan guarantees to Ukraine unless it fired a prosecutor investigating a gas company on which Hunter Biden had a seat.

Trump also accuses Hunter Biden of taking $1.5 billion from China "for no apparent reason" and has publicly called on China to investigate the Bidens.

"There is NO WAY these can be legitimate transactions? As lawyers & others have stated as President I have an OBLIGATION to look into possible or probable CORRUPTION," he tweeted.

No evidence of corruption by the Bidens in Ukraine or China has been found. (VOA)

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