U.S. President-elect Joe Biden's son Hunter Biden said on Wednesday the U.S. Attorney's Office in Delaware is investigating his tax affairs.

"I take this matter very seriously but I am confident that a professional and objective review of these matters will demonstrate that I handled my affairs legally and appropriately, including with the benefit of professional tax advisors," Hunter Biden said in a statement.

He said he learned of the investigation on Tuesday when prosecutors informed his lawyer of the probe.

The transition team for Biden on Wednesday released a statement saying Biden "is deeply proud of his son, who has fought through difficult challenges, including the vicious personal attacks of recent months, only to emerge stronger."

The investigation began as early as 2018 and investigators have been examining multiple financial issues, including whether Hunter Biden and his associates violated tax and money laundering laws in business dealings in foreign countries.

The U.S. Attorney's Office declined to comment, and Hunter Biden's attorney could not immediately be reached for comment, according to Reuters.

(With input from agencies)