President Donald Trump talks to reporters on the South Lawn of the White House, Friday, Oct. 4, 2019, in Washington. (AP Photo…
FILE - President Donald Trump talks to reporters on the South Lawn of the White House, Oct. 4, 2019.

White House correspondent Steve Herman contributed to this report.

A second U.S. intelligence whistleblower has come forward with concerns about U.S. President Donald Trump's July telephone call with Ukrainian President Volodymyr Zelenskiy.

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

Zaid says the new whistleblower has what the lawyer calls "firsthand knowledge" of the Trump phone call, substantiating the original whistleblower's complaint – that Trump reached out to a foreign government to dig up dirt on 2020 presidential candidate Joe Biden.

Ukrainian President Volodymyr Zelenskiy speaks to media during his press conference in Kyiv, Ukraine, Oct. 1, 2019.

Until now, Trump has complained that the first whistleblower came forward with so-called third hand information about Trump's call to Zelenskiy. The call shows Trump asking Zelenskiy to look into alleged corruption in Ukraine by Biden and his son Hunter, setting off a Democratic-led House impeachment inquiry into Trump.

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 publically 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.

Hunter Biden and several partners reportedly met with a Chinese private equity investor on starting a global investment fund with capital from China and other countries.

According to the New Yorker magazine, a Biden lawyer says Hunter joined the board of investors after his father was no longer vice president.

Trump insists there was nothing wrong with his July 25th phone call with Zelenskiy, describing it as "perfect," and accusing House Democrats of trying to orchestrate a "coup."

Some of Trump's Republican supporters in the House and Senate say his conversation was strictly about corruption and nothing to do with politics.

But House Democrats say the call was a direct appeal by the president to a foreign country to interfere in the 2020 presidential election by asking to investigate his rival.

They also allege the president froze badly needed U.S. military aid to Ukraine unless Ukraine committed to investigating the Bidens.

Both the Ukrainian and Chinese governments have said they want to stay out of U.S. politics.

U.S. Energy Secretary Rick Perry speaks at the California GOP fall convention, Sept. 6, 2019, in Indian Wells, California.

Trump said late last week that it was U.S. Energy Secretary Rick Perry who encouraged him to telephone Zelenskiy.

A Perry spokeswoman said Sunday the secretary pushed Trump to discuss energy security and economic matters with Ukraine.

Perry told the Christian Broadcasting Network that he never heard anyone in the administration mention Biden's name when talking about Ukraine.