The newly revealed exchanges provide additional information about the role played by Trump Jr. in 2016. He also has come under scrutiny for agreeing to meet with a Russian lawyer in Trump Tower who he was told wanted to provide “dirt” about Democratic nominee Hillary Clinton on behalf of the Russian government, according to WP.

Donald Trump Jr. did not respond to many of the notes, which were sent using the direct message feature on Twitter. But he alerted senior advisers on his father’s campaign, including his brother-in-law, Jared Kushner, according to two people familiar with the exchanges.

In the messages, WikiLeaks urged Trump Jr. to promote its trove of hacked Democratic emails and suggested that President Trump challenge the election results if he did not win, among other ideas. They were first reported by the Atlantic and later posted by Trump Jr. on Twitter.

Read alsoBloomberg: Manafort charges renew questions about Skadden's work in UkraineWikiLeaks, which bills itself as an anti-secrecy group, was described in April by CIA Director Mike Pompeo as a “non-state hostile intelligence service often abetted by state actors like Russia.”

In July 2016, the organization released thousands of emails that had been stolen from the Democratic National Committee by a cyberhack that U.S. intelligence officials concluded was orchestrated by the Russian government.

At one point during his communication with WikiLeaks, Trump Jr. sought to learn more about a rumored leak of new documents related to Clinton, the messages indicate.

“What’s behind this Wednesday leak I keep reading about?” Trump Jr. asked during one exchange with the WikiLeaks account on Oct. 3.

More than a week later, on Oct. 12, the account replied with a suggestion:

“Hey Donald, great to see you and your dad talking about our publications,” WikiLeaks wrote. “Strongly suggest your dad tweets this link if he mentions us.” The message included a link to search documents that had been hacked from Clinton campaign chairman John Podesta.

Trump Jr. did not answer. Fifteen minutes later, his father tweeted to his millions of followers: “Very little pick-up by the dishonest media of incredible information provided by WikiLeaks. So dishonest! Rigged system!”

Read alsoEx-intelligence chiefs say Trump is being manipulated by Putin - mediaTwo days later, Trump Jr. tweeted the link to his followers, writing, “For those who have the time to read about all the corruption and hypocrisy all the @wikileaks emails are right here:”

On Monday, Adam Schiff, the top Democrat on the House Intelligence Committee, said the messages were “yet another secret communication between the Trump campaign and cut-outs for the Kremlin.”

Clinton Watts, a former FBI agent who has been tracking the Russian influence effort, called Trump Jr.’s messages “unprecedented.”

Read alsoRussia trolls deflected Trump bad news during campaign“I can’t think of any time in history where a foreign government, through a cut-out has been able to tap directly into a campaign in this way,” he said. “It shows they were complicit to this and how amenable they were to hurting another American, even if the source came from a foreign government.”