US President Donald Trump, his son and top aides have consistently denied claims that his campaign had talks with Russian officials trying to favour him in last year's election.
But the revelation that Donald Trump Jr met a Russian lawyer who had promised damaging material about his father's opponent, Hillary Clinton, has renewed speculation of collusion between the Trump camp and Russia.
Here are some of the denials made by key players on President Trump's team.
Donald Trump Jr
24 July 2016: On CNN's State of the Union, Mr Trump Jr is asked about a suggestion by the Clinton campaign that Russia is trying to help his father's election, an effort that included the hacking and publication of emails of the Democratic National Committee (DNC).
"It just goes to show you their exact moral compass," he replies. "They'll say anything to be able to win this. This is time and time again, lie after lie... It's disgusting, it's so phoney… I can't think of bigger lies. But that exactly goes to show you what the DNC and what the Clinton camp will do. They will lie and do anything to win."
March 2017: When asked about meeting Russian nationals for campaign-related conversations, Mr Trump Jr tells the New York Times: "Did I meet with people that were Russian? I'm sure, I'm sure I did... But none that were set up. None that I can think of at the moment. And certainly none that I was representing the campaign in any way, shape or form."
He also denies having discussed Russia-related government policies, saying "100% no".
9 July: Mr Trump Jr releases a statement saying that the Russian lawyer he met with had claimed to have damaging information about Hillary Clinton. "My father knew nothing of the meeting or these events", he writes.
11 July: Mr Trump Jr tweets the transcripts of the email correspondence arranging for the meeting with a Russian lawyer. Later in the evening he tells Fox News Channel's Hannity that the meeting was "opposition research", but that in retrospect he "would have done things a little differently".
27 July 2016: Mr Trump tells a CBS affiliate in Miami: "I can tell you I think if I came up with that they'd say, 'Oh, it's a conspiracy theory, it's ridiculous.'... I mean I have nothing to do with Russia. I don't have any jobs in Russia. I'm all over the world but we're not involved in Russia."
24 October: At a campaign rally in Florida, the Republican says: "I have nothing to do with Russia, folks, I'll give you a written statement."
11 January 2017: Mr Trump tweets:
Later, in a press conference, Mr Trump does not answer a question about having contacts with the Russians during the campaign.
7 February:Mr Trump tweets again: "I don't know Putin, have no deals in Russia, and the haters are going crazy - yet Obama can make a deal with Iran, #1 in terror, no problem!"
16 February: Mr Trump, again on Twitter, says: "The Democrats had to come up with a story as to why they lost the election, and so badly (306), so they made up a story - RUSSIA. Fake news!"
26 February: The president repeats that the allegations are "fake news", saying on Twitter: "Russia talk is FAKE NEWS put out by the Dems, and played up by the media, in order to mask the big election defeat and the illegal leaks!"
8 May:Mr Trump tweets: "The Russia-Trump collusion story is a total hoax, when will this taxpayer funded charade end?"
11 May: Mr Trump says in an interview with NBC News: "This Russia thing with Trump and Russia is a made-up story, it's an excuse by the Democrats for having lost an election that they should have won."
18 May: The president calls the enquiry into the alleged Russian interference in the US election a "witch hunt."
12 July: "No, that I didn't know until a couple of days ago when I heard about this," Mr Trump tells Reuters news agency about the meeting between Donald Trump Jr, campaign officials, and the Russian lawyer.
Mike Pence, US vice-president
15 January 2017: When asked on CBS' Face the Nation if any member of the Trump campaign had contacts with Russian officials trying to interfere in the election, Mr Pence says: "Of course not. And I think to suggest that is to give credence to some of these bizarre rumours that have swirled around the candidacy." He denies the claim in several other interviews.
11 July 2017: The vice-president's spokesman, Marc Lotter, points out that Mr Trump Jr's meeting happened before Mr Pence joined the ticket.
12 July 2017: Asked three times during a Fox News interview if Mr Pence had ever met with Russian government officials, during the campaign, Mr Lotter thrice declines to answer.
13 July 2017: Mr Lotters, the vice-president's spokesman, releases this statement: "The Vice President had no meetings with any individual associated with the Russian government during the campaign or transition."
Kellyanne Conway, senior White House adviser
18 December 2016: When asked if the campaign had any contact with Russian officials trying to influence the election outcome, she tells CBS' Face the Nation: "Absolutely not. I discussed that with the president-elect just last night. Those conversations never happened."