However, Johnson didn't say that in testimony Wednesday before the House intelligence committee; Johnson said was he wasn't aware of efforts by Trump or his campaign to collude with Russian Federation beyond what the intelligence community already knows.
"The DNC has and will continue to cooperate with law enforcement on Russia's interference in our election", DNC spokeswoman Adrienne Watson said in a statement responding to Trump's tweet. "Most of the intelligence products that are relied upon to form certain assessments, that underlying data was available in 2016, some of it before the election".
"I recall clearly that I was not pleased that we were not in there helping patch this vulnerability", Johnson said.
While there is an ongoing investigation into ties between members of Donald Trump's presidential campaign team and members of the Russian government, there is no evidence to suggest the stolen voter records were provided to the Trump campaign-though Congressional investigators are investigating that possibility. "I can imagine that some do it deliberately, staging a chain of attacks in such a way as to cast Russia as the origin of such an attack", the Russian leader said last month.
As homeland security secretary, Johnson lacked access to much of the intelligence being gathered.
Russia's computer-hacking operation leading up to the election led to the release by the file-sharing group WikiLeaks of thousands of emails captured from the files of Democratic party chairman John Podesta, who was the campaign chairman for Trump's challenger, former U.S. Secretary of State Hillary Clinton.
Senator Angus King, an independent from ME who caucuses with the Democrats, voiced skepticism, saying only a small number of votes in key battleground states would need to be altered to tip the scales in an election.
Russian hackers targeted election-related systems in 21 states during the 2016 presidential election, a USA official has confirmed. "Why didn't they stop them?" "It's all a big Dem HOAX!", Trump said.
Senators said the Homeland Security Department should reveal which state election systems were targeted by hackers as Jeanette Manfra, the department's undersecretary for cybersecurity, demurred. "It's all a big Dem HOAX!"
"The DNC was contacted by [the Department of Homeland Security] months after the DNC worked closely with the Federal Bureau of Investigation to remedy the intrusion".
"One of the candidates, as you'll recall, was predicting that the election was going to be rigged in some way".
"In retrospect, it would be easy for me to say that I should have bought a sleeping bag and camped out in front of the DNC in late summer - with the benefit of hindsight", he said.
He described Russia's attempts to influence the election as its "boldest to date" in the US.
In the aftermath of their loss to Donald Trump in November, Democrats have cited the email hack as a main reason why they lost, yet still haven't turned over the DNC server for investigation or analysis.
But he also added, "I am not in a position to know whether the successful Russian government-directed hacks of the DNC and elsewhere did in fact alter public opinion and thereby alter the outcome of the presidential election".
Special Counsel Robert Mueller, a former FBI director, met on Wednesday with senior Senate Judiciary Committee members to ensure there was no conflict between his investigation of potential collusion between Russian Federation and the Trump campaign and the panel's probe of what led to Trump firing Federal Bureau of Investigation Director James Comey.