Getty Images
Now playing
00:43
Trump: Clinton, Dems colluded against Sanders
Now playing
05:18
Anderson Cooper explains how he overcomes being shy
LONDON, ENGLAND - DECEMBER 07:  A visual representation of the digital Cryptocurrency, Bitcoin on December 07, 2017 in London, England. Cryptocurrencies including Bitcoin, Ethereum, and Lightcoin have seen unprecedented growth in 2017, despite remaining extremely volatile. While digital currencies across the board have divided opinion between financial institutions, and now have a market cap of around 175 Billion USD, the crypto sector coninues to grow, as it continues to see wider mainstreem adoption. The price of one Bitcoin passed 15,000 USD across many exchanges today taking it higher than previous all time highs.  (Photo by Dan Kitwood/Getty Images)
Dan Kitwood/Getty Images
LONDON, ENGLAND - DECEMBER 07: A visual representation of the digital Cryptocurrency, Bitcoin on December 07, 2017 in London, England. Cryptocurrencies including Bitcoin, Ethereum, and Lightcoin have seen unprecedented growth in 2017, despite remaining extremely volatile. While digital currencies across the board have divided opinion between financial institutions, and now have a market cap of around 175 Billion USD, the crypto sector coninues to grow, as it continues to see wider mainstreem adoption. The price of one Bitcoin passed 15,000 USD across many exchanges today taking it higher than previous all time highs. (Photo by Dan Kitwood/Getty Images)
Now playing
03:07
Bitcoin has an energy problem
Now playing
01:32
Scientists turned spiderwebs into music and it sounds like a nightmare
Jeopardy Productions, Inc.
Now playing
01:02
Aaron Rodgers' Green Bay Packers question stumps 'Jeopardy!' contestants
Now playing
05:18
Coinbase CFO: We're an on-ramp to the crypto economy
Kristina Barboza
Now playing
03:09
Grieving mom's advice to other families: You can try to help, support and love
CNN
Now playing
02:12
'Too dangerous to do anymore': Sacha Baron Cohen on Borat
Christopher Hamilton
Now playing
01:01
Volcanologist shares what he prefers to cook on lava flows
John Avlon 0413 Wallace
CNN
John Avlon 0413 Wallace
Now playing
03:31
Avlon compares Tucker Carlson's comments to George Wallace
screengrab hong kong oscars
IMDB / Field of Vision
screengrab hong kong oscars
Now playing
02:50
Hong Kong won't air Oscars for the first time since 1968
Now playing
01:27
See the first community of 3D-printed homes
Burlington, MA Headquarters
Nuance
Burlington, MA Headquarters
Now playing
01:34
Microsoft to buy AI company Nuance
Now playing
02:50
Sleep doctor tells Anderson Cooper how long a power nap should be
WASHINGTON, DC - DECEMBER 01: Chairman of the Federal Reserve Jerome Powell testifies during a Senate Banking Committee hearing about the quarterly CARES Act report on Capitol Hill December 1, 2020 in Washington, DC.  Treasury Secretary Steven Mnuchin also testified at the hearing. (Photo by Susan Walsh-Pool/Getty Images)
Susan Walsh/Pool/Getty Images
WASHINGTON, DC - DECEMBER 01: Chairman of the Federal Reserve Jerome Powell testifies during a Senate Banking Committee hearing about the quarterly CARES Act report on Capitol Hill December 1, 2020 in Washington, DC. Treasury Secretary Steven Mnuchin also testified at the hearing. (Photo by Susan Walsh-Pool/Getty Images)
Now playing
02:06
Fed chief: The economy is about to grow more quickly
"Saturday Night Live" / NBC
Now playing
01:47
'SNL' sees Minnesota news anchors take on the Derek Chauvin trial

Story highlights

Sen. Sanders' supporters said hacked DNC emails showed the party favored Clinton in the presidential primary

Former Clinton campaign manager Robby Mook, a CNN political commentator, said Trump should address threats to US elections

Trump's tweet comes as Congress and special counsel Robert Mueller probe Russia's efforts to influence the US election

(CNN) —  

President Donald Trump lashed out at Hillary Clinton and the Democratic Party in a tweet Sunday morning, saying the former secretary of state “colluded” with the party in the presidential primary to defeat Sen. Bernie Sanders.

“Is she allowed to so collude?” the President asked. “Unfair to Bernie!”

The tweet is an apparent reference to a cache of nearly 20,000 hacked Democratic National Committee emails released by WikiLeaks nearly one year ago that Sanders’ supporters’ said bolstered their claims that the party favored Clinton.

The tweet comes as congressional committees and Department of Justice special counsel Robert Mueller continue investigations into Russia’s efforts to influence the US election and the Trump campaign’s contacts with Russian officials, including allegations of collusion between his campaign and Russia in an effort to defeat Clinton during the presidential campaign. Trump, his campaign and Russian officials have denied any collusion took place between them.

Without mentioning Sanders’ name, one of the hacked DNC emails appeared to show a DNC staffer asking others to ask the candidate about his faith, saying it would weaken him in the eyes of Southern voters. Another seemed to depict an attorney for Clinton’s campaign advising the committee on how to defend her against an accusation by the Sanders campaign of not living up to a joint fundraising agreement.

The fallout from the release of the emails prompted Sanders and his supporters to call for DNC Chairwoman Debbie Wasserman Schultz of Florida to resign as party chair. Schultz, a Clinton ally, stepped down from that position at the conclusion of the Democratic National Convention.

Clinton spokesman Nick Merrill declined to comment for this story.

Former Clinton campaign manager Robby Mook, a CNN political commentator, said Trump should move on from the election and address concerns over threats to the nation’s elections.

“The Washington Post called the Russian intervention in the 2016 election the ‘crime of the century,’ and much of our campaign and election infrastructure still remains as vulnerable today as it was then,” Mook told CNN. “Rather than stoking divisions from the last election, the President should be bringing the country together to defend our country and our democracy.”