Representatives of the Ukrainian authorities are not going to testify before the United States Congress on their own initiative in the case of U.S. President Donald Trump's impeachment, Ukrainian Foreign Minister Vadym Prystaiko said.

"I was aware. All necessary channels, both official and unofficial, are being used continuously," Prystaiko told journalists in Mariupol on Tuesday.

Contact with the U.S. side is being held as normal, he said.

Commenting on the possibility of Ukrainian politicians testifying in the case of the U.S. president's impeachment, Prystaiko said, "We could tell them if they ask us. It's nothing to do with us. Let them deal with it themselves, we won't be going there, won't comment."

The telephone call between Trump and Ukrainian President Volodymyr Zelensky caused a political scandal in the U.S. this fall. According to press reports citing a whistleblower, Trump was trying to pressure Zelensky into starting an investigation against Joe Biden, a key Democratic candidate in the upcoming presidential race, and his son, Hunter.