The Senate released transcripts on Wednesday of its interviews with Donald Trump Jr. and others regarding a controversial Trump Tower meeting during the 2016 presidential campaign.

The meeting has become a key thread of inquiry in the special counsel Robert Mueller's Russia investigation.

Trump Jr. told the committee that he didn't believe there was anything wrong with attending the meeting and that he didn't know whether his father was involved in crafting the initial statement after news of the meeting broke.

The Senate Judiciary Committee on Wednesday released hundreds of pages of transcripts from interviews regarding a controversial June 2016 meeting at Trump Tower between Donald Trump Jr. and a Russian lawyer who was said to have offered dirt on Hillary Clinton, then the Democratic presidential nominee.

The meeting has become a crucial part of the special counsel Robert Mueller's investigation into Russia's meddling in the 2016 US election, whether the Trump campaign colluded with Moscow, and whether there were attempts to obstruct justice.

The committee released roughly 1,800 pages of documents from interviews with several of the meetings' attendees, including Trump Jr., the British publicist Rod Goldstone, the Russian-American lobbyist Rinat Akhmetshin, the translator Anatoli Samochornov, and the Russian executive Ike Kaveladze.

Other meeting attendees who declined to be interviewed by the Senate committee included top Trump campaign officials Jared Kushner and Paul Manafort.

The Russian lawyer at the center of the meeting, Natalia Veselnitskaya, was not interviewed but provided written responses to questions.

The Trump Tower meeting had ostensibly been set up to provide dirt on Clinton, to which Trump Jr. told Goldstone in an email, "If it's what you say I love it."

But the attendees have said Veselnitskaya never provided dirt on Clinton and instead discussed Russian adoption policy and the lifting of US sanctions imposed by the Magnitsky Act.

Here are some of the highlights from the transcripts:

Trump Jr. told the Senate Judiciary Committee that he didn't believe there was anything wrong with attending the Trump Tower meeting.

He also testified that he didn't recall whether he had discussed the Russia investigation with his father. When asked whether President Donald Trump was involved in drafting the initial statement after news broke last year of the meeting, Trump Jr. said: "I don't know. I never spoke to my father about it."

When asked by lawmakers what he meant by "If it's what you say I love it," Trump Jr. said he was using a "colloquial term used to say, 'Hey, great, thank you.'" Trump Jr. added that he had "other stuff" on his plate at the time and "didn't want to deal with anything right now."

Trump Jr. testified that he didn't tell his father in advance about the Trump Tower meeting. He said he believed that he told only Kushner and Manafort about it, inviting them to attend.

Senate investigators grilled Trump Jr. about a series of phone calls to and from Trump Jr.'s phone shortly after Goldstone's email on June 6, 2016. Trump Jr. confirmed that he received a call from the Russian singer Emin Agalarov at 4:04 p.m. and called Agalarov back at 4:31 p.m., but Trump Jr. said he had "no idea" with whom he had a four-minute call at 4:27 p.m. from a blocked number.

Trump Jr. also testified that he was disappointed the meeting didn't yield the type of dirt on Clinton that he was promised. "All else being equal," he said, "I wouldn't have wanted to waste 20 minutes hearing about something that I wasn't supposed to be meeting about."

Goldstone testified that he believed the Trump Tower meeting was a "bad idea" at the time and that "we shouldn't do it." He added that he "knew nothing" about politics and was only a music publicist.

But Goldstone also testified that he, like Trump Jr., attended the meeting expecting Veselnitskaya would deliver a "smoking gun" to help Trump's campaign. He testified later that "this was the most embarrassing thing" he'd been asked to do by his client Agalarov.

Goldstone testified that during the Trump Tower meeting, Kushner "appeared somewhat agitated" by Veselnitskaya's "labored presentation" and told her: "I really have no idea what you're talking about. Could you please focus a bit more and maybe just start again?" Goldstone said Veselnitskaya then repeated her previous points, which seemed to "infuriate" Kushner.

After news broke in July about the Trump Tower meeting, Goldstone texted Agalarov, saying, "I hope this favor was worth it for your dad," the Russian billionaire Aras Agalarov. Goldstone added that "it could blow up."

Emin Agalarov had tried to get Trump to meet with Russian President Vladimir Putin during the 2013 Miss Universe pageant in Moscow, according to Kaveladze, who testified that Agalarov "secretly requested" the meeting.

Though Putin agreed to attend a rehearsal, he canceled. There is no evidence Trump and Putin met until after Trump became president.

Goldstone also brought up the possibility of a meeting between Trump and Putin in a July 2015 email to Trump's personal assistant inviting him to a birthday party in Moscow. When Trump's assistant said it was unlikely Trump would be able to attend, Goldstone followed by saying, "Unless maybe he would welcome a meeting with President Putin, which Emin would set up."

In a statement on Wednesday, Trump Jr. said the transcripts showed he answered "every question asked."

"I appreciate the opportunity to have assisted the Judiciary Committee in its inquiry," he said. "The public can now see that for over five hours I answered every question asked and was candid and forthright with the committee."

Read Trump Jr.'s full testimony below: