The Senate Armed Services Committee has already began questioning intelligence officials in a public hearing Thursday morning. Later Thursday, the Senate Foreign Relations Committee will receive a private, classified briefing.
During his opening statement to the Senate Armed Services Committee Thursday morning, National Intelligence Director James Clapper said that Russia has "clearly assumed an even more aggressive cyber posture."
Clapper said he is not prepared to specifically discuss Russia's apparent interference in the U.S. election in November, but spoke more generally about the cyber threats posed by Russia, as well as China, Iran, North Korea and non-state actors like ISIS.
"Our collective security is better, but it is not good enough," Clapper said.
Clapper told the Armed Services Committee that the government should "consider all instruments of national power" in dealing with major cyber attacks and proposed separating the United States Cyber Command from the National Security Agency.
According to Clapper, Congress will be briefed on Russian interference in the U.S. election and an unclassified version of the report will be released to the public early next week.
It is unclear how much information will be provided to the public, but the hearings will likely provide a first look into what evidence intelligence officials have that the Russian government was working behind the scenes to help Donald Trump defeat Hillary Clinton.
Graham described President Barack Obama's response to the alleged interference as throwing a "pebble."
"I'm ready to throw a rock," Graham said.
The hearings will also provide a glimpse into what Congress, including top Republicans like Sens. John McCain and Lindsey Graham — who have sparred with Trump over the intelligence reports — may plan to do about the alleged Russian interference. Trump has called the intelligence reports a "conspiracy theory" and questioned why the intelligence only emerged after the election, despite having been briefed on the Russian cyberhacking during the campaign.
On Thursday morning, Trump once again tweeted about the hacking reports, blaming the "dishonest media" for making it "look like I am against 'intelligence.'"
During the hearing, Clapper shot back at Trump, saying there was a difference between expressing "healthy skepticism" about intelligence and the "disparagement" of the intelligence community.
"The intelligence community is not perfect," Clapper said. "We are an organization of human beings and we're prone sometimes to make errors."
Senator Claire McCaskill, a Missouri democrat, accused Trump of "trashing the intelligence community" and said there would be "howls from the Republican side of the aisle" had a Democrat made such comments.
The U.S. intelligence community in December formally announced its conclusion the Russian government was behind the hacks that led to the release of emails from the Clinton campaign and the Democratic National Committee over the summer. Officials now say they have evidence Russia provided the emails to WikiLeaks through a third party, Reuters reported Wednesday. The Russians are also believed to have helped spread fake news stories to hurt the Clinton campaign, according to reports.
Clapper said Thursday that the Russian fake news campaign is ongoing.
On Dec. 29, President Barack Obama responded by expelling Russian diplomats and intelligence operatives from the U.S. and imposing sanctions on Russia in what one expert called the "biggest retaliatory move against Russian espionage since the Cold War." Russian President Vladimir Putin said Russia would not respond and that "the restoration of Russian-American relations will... be carried out by the administration of President D. Trump."
Trump praised Putin for his response to the Obama administration's move.
Jan. 5, 2017, 2:48 p.m.: This story has been updated.