Donald Trump Jr has offered to testify under oath, following the release of emails that confirmed a meeting between himself and Russians during the 2016 US election campaign in a bid to find information discrediting Hillary Clinton.

Trump Jr was appearing on an interview with Fox News host Sean Hannity when the host said: "And you have nothing to hide. That means you'll testify under oath, all of that?"

Donald Trump's eldest son responded saying: "All of it."

Congressmen and committees were already interested in hearing from the president's son before the stunning release of emails, which confirmed he had met with a Russian lawyer who was offering information to undermine the Clinton campaign.

The most explicit email was sent on 3 June, which said there was information that "would incriminate Hillary and her dealings with Russia and would be very useful to your father [Donald Trump Sr].

"This is obviously very high level and sensitive information but is part of Russia and its government's support for Mr Trump."

Trump Jr responded saying: "If it's what you say I love it especially later in the summer."

The emails showed that he was ready to accept information from foreign agents to help his father win the White House.

Trump Jr said that everything had been dealt with appropriately and that the meeting didn't yield the information he had hoped for, but looking back he would "have done things a little differently".

Speaking about the meeting, Trump Jr said: "They had something — maybe concrete evidence to all the stories that I'd been hearing about, but they were probably underreported for years, not just during the campaign. So I think I wanted to hear it out."

The release of the emails directly undermine the previous statements of the White House, who in recent months have been adamant that no-one inside the Trump campaign had any contact with Russians.

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Donald Trump Jr. arrives at Trump Tower on January 18, 2017 in New York City. Getty Images