Jay Sekulow, a member of President Trump's legal team, told reporters the team plans to invoke the Bidens during the impeachment trial in the Senate.

"For the life of me, they've done it. Why, they opened up the door as wide as a double door on the Hunter Biden, Joe Biden, Burisma issue. I guess that was their way of getting ahead of it. We will address it," Sekulow told reporters.

Earlier, he also spoke on what he believes are "issues" surrounding the Ukraine controversy. Sekulow questioned the Democratic Party's involvement in the funding of the dossier by British ex-spy Christopher Steele.

"You should be able to get a sense from what I'm saying right now ... that we're going to rebut and refute, and we're going to put on an affirmative case tomorrow. But that's just one, just one issue."

Hunter Biden, 49, worked on the board of Ukrainian energy company Burisma while his father Joe Biden was vice president. Hunter Biden was being paid $50,000 each month he was on the board of the energy company.