Sen. Mark Warner, D-Va., vice chairman of the Senate Select Committee on Intelligence, wrote a letter addressed to Secretary of the Department of Homeland Security, John Kelly, urging a full and public disclosure on the foreign attempts to interfere in the 2016 U.S. presidential election.

Warner wrote that, despite his limited knowledge of the evidence pertaining to the manipulation of the 2016 election, he is aware that "DHS and the FBI have confirmed two intrusions into voter registration databases in Arizona and Illinois by foreign-based hackers, though no data was modified or deleted," while other suspicious activity was found aimed at more states' election data bases.

"We are not made safer by keeping the scope and breadth of these attacks secret," Warner wrote, underscoring his deep concern. He continued, saying that the attempted cyberattack on the 2016 elections gives a clear indication of the Russian government's intentions to undermine America's confidence in the democratic government.

To combat the Russian manipulation, Warner urged Kelly to "harden our cyber defenses and to thoroughly educate the American public about the danger posed by these attacks." A full disclosure to the public, according to Warner's letter, will help to neutralize the threats these attacks pose.

His letter concludes as he asks Secretary Kelly to update the Intelligence Committee on whatever actions have been taken to secure the election infrastructure since it was deemed to be a "critical infrastructure" back in January.

Warner's letter precedes an Intelligence Committee open hearing on the topic "U.S. Election Security: Russian interventions and the Outlook for 2018 and Beyond" that is to take place Wednesday at 9:30 a.m.

The hearing will be divided into two panels that will detail the response efforts to the Russian cyberattacks against the election systems while also detailing any potential threats that can be seen in the future elections, specifically the 2018 and 2020 elections, and how they will be combated. The first panel will have expert witnesses from DHS and the FBI. This will be followed by the second panel where witnesses from the Illinois State Board of Elections, the National Association of State Election Directors, and an expert witness on election security will speak.