WASHINGTON, July 12 (Reuters) - U.S. President Donald Trump on Wednesday defended Donald Trump Jr. as "innocent" following revelations in emails that showed his eldest son welcomed Russian help against his father's rival in last year's presidential election.

"My son Donald did a good job last night," Trump wrote on Twitter, referring to a television interview by his son late Tuesday on the issue. "He was open, transparent and innocent. This is the greatest Witch Hunt in political history. Sad!" (Reporting by Susan Heavey; Editing by Catherine Evans)

Our Standards: The Thomson Reuters Trust Principles.