Attorney General Jeff Sessions on Tuesday said suggestions he met with Russian officials to influence the 2016 election are like a story written by Lewis Carroll.
He did not identify any individuals who may have accused him of colluding with the Kremlin.
Throughout the questioning, Sessions defended himself and refused to discuss any details of conversations he has had with President Trump.
Attorney General Jeff Sessions is preparing for sharp questions from his former Senate colleagues about his role in the firing of James Comey and his Russian contacts during the campaign.
Deputy Attorney General Rod Rosenstein says that a history of political giving is not a disqualifier for those who work for the Department of Justice's special counsel investigating Russian interference in US elections.
"I think it depends on the scope of the questions", Spicer said.
"The suggestion that I participated in any collusion, that I was aware of any collusion with the Russian government, or hurt this country which I have served with honor for 35 years, or to undermine the integrity of our democratic process, is an appalling and detestable lie", Sessions said.
Such a move would create a firestorm coming weeks after Trump fired FBI Director James Comey.
"I can not and will not violate my duty to protect the confidential communications I had with the president", Sessions said in his opening statement.
Sessions certainly isn't expected to hit his boss while testifying on live television, but look for senators to try and get at how much pressure Trump has put on him.
Wyden responded: "He said it's "problematic" and I asked you what was problematic about it".
Sessions is the most senior member of President Donald Trump's administration caught up in the controversy over whether associates of the president colluded with Russian Federation to help Trump win the election.
"Our committee will want to hear what you are doing to ensure that the Russians - or any other foreign adversaries - can not attack our democratic process like this ever again".
Russian Federation has denied interfering in the US election. But since the President can not directly fire the special counsel, the question lands squarely at the feet of Sessions and Deputy Attorney General Rod Rosenstein.
In a February meeting, Comey said, Trump told Sessions and other administration officials to leave the room before asking him to drop a probe into former National Security Adviser Michael Flynn's contacts with Russian Federation.
The attorney general has acknowledged two meetings a year ago with Russia's ambassador to the U.S., Sergey Kislyak.
CNN previously reported that congressional investigators are examining whether Sessions had an additional private meeting with the Russian ambassador in April 2016 at the Mayflower Hotel in Washington.
"I believe the American people have had it with stonewalling", Wyden said.
Sessions says the president was not asserting executive privilege and that Sessions was simply protecting Trump's right to do so if he chooses. "If there were not good cause it wouldn't matter what anyone said".
When asked if he would do if Trump ordered him to fire Mueller, Rosenstein said, "I am not going to follow any orders unless I believe those are lawful and appropriate orders".
Committee chairman Sen. Richard Burr of North Carolina laid out questions that he wanted addressed, including Sessions' meetings with Russian officials or proxies while working for the Trump campaign or as Attorney General. I'm following historic policies of Department of Justice. As Trump tried to shoo everyone out to talk alone with Comey, Sessions lingered, in Comey's account. Senate Democrats have been champing at the bit for more than a month now to get an answer to what exactly Sessions meant when he said he was recusing himself. "I can assure you that none of those meetings discussed manipulating those campaigns in any shape or form". "I affirmed his concern that we should be following the proper guidelines of the Department of Justice, and basically backed him up in his concerns".
Sessions said he agreed with a letter drafted by his deputy, Rod Rosenstein, that Comey should be replaced.