Joe Biden refused to answer questions on Wednesday after calling on Congress to impeach President Donald Trump.

The former vice president made the announcement shortly after House Democrats signaled they would begin an impeachment inquiry into Trump for urging Ukraine’s government to probe Hunter Biden’s business dealings.

“If President Trump refuses to comply with congressional requests, then he “will leave Congress, in my view, no choice but to initiate impeachment,” Biden said, before refusing to address questions from reporters. “That would be a tragedy, but a tragedy of his own making.”

Last week, the Wall Street Journal reported Trump asked Ukrainian President Volodymyr Zelensky to look into Hunter Biden’s ties to Burisma Holdings. The younger Biden joined the natural gas company’s board of directors in April 2014, where he was purportedly paid more $83,000 a month, despite having no prior background in the energy industry.

At the same time, Joe Biden was the Obama administration’s point-man on Ukraine in the wake of Russia’s annexation of Crimea. More troubling is that the former vice president pressured the Ukrainian government in 2016 to fire its top prosecutor, Viktor Shokin, who was known to be investigating the energy giant.

Given the appearance of a conflicts of interest and the contradicting stories Joe and Hunter Biden have spun on the topic, Trump has defended his calls for Ukraine to investigate.

Trump said on Saturday:

The conversation I had was largely congratulatory, with largely corruption, all of the corruption taking place and largely the fact that we don’t want our people like Vice President Biden and his son creating the corruption already in the Ukraine and Ukraine has got a lot of problems.

Shortly before the former vice president drew the line in the sand on impeachment, Trump announced he would release the un-redacted transcript of his call with Ukraine’s newly-elected president. The released documents, however, are only likely to draw more scrutiny to the unanswered questions about the reasoning for Hunter Biden’s appointment to Burisma’s board of directors.

As evidenced by the former vice president’s decision to avoid the press on Thursday, such answers are likely not forthcoming.

Since announcing his presidential campaign, the former vice president has refused to discuss his son’s business ties to either Ukraine or China, despite mounting evidence such dealings were made easier because of his political influence. As Peter Schweizer detailed in his book, Secret Empires: How the American Political Class Hides Corruption and Enriches Family and Friends, Hunter Biden made a lucrative profit off extraordinary deals that were unavailable to regular businessmen.

“I mean, you look at — around the world, there are two countries where Joe Biden is the point person for the Obama administration: China and Ukraine, and in both cases, his son lands huge deals in both countries. I mean, what are the odds of that?” Schweitzer said during a recent interview on Fox & Friends.