A Senate panel has released documents on a June 2016 meeting between Trump campaign aides and a Russian delegation promising to help their campaign.

The 2,500 pages of transcripts confirm that Donald Trump Jr and campaign aides wanted "dirt" on his father's Democratic opponent Hillary Clinton.

The meeting is a part of an ongoing probe by the Justice Department into alleged Russia meddling in 2016.

The committee released the documents after additional witness interviews.

The Senate Judiciary Committee, which is conducting one of several investigations into Russia's alleged interference in the US election, interviewed Mr Trump Jr and four other people who attended the 9 June meeting at Trump Tower in New York.

Rob Goldstone, who arranged the meeting with Russian lawyer Natalia Veselnitskaya, Russian-American lobbyist Rinat Akhmetshin, Georgian-American businessman Ike Kaveladze and a translator testified before the panel.

Ms Veselnitskaya was not interviewed, but the committee released her written responses to a letter that Senate Judiciary Chairman Chuck Grassley sent her last year.

"Americans rightly have many questions about this meeting, and today, we are releasing the transcripts and exhibits from interviews we've conducted to allow the public to know what we know," Senator Grassley said in a statement on Wednesday after releasing the documents.

"These materials, taken in their entirety, provide the most complete public picture of the events surrounding the meeting to date."

The committee also did not interview the president's son-in-law, Jared Kushner, and then-campaign manager Paul Manafort, who both attended the 2016 meeting.