"You're impeding this investigation", Heinrich said.
His testimony came just six days after James Comey, the fired Federal Bureau of Investigation director, appeared before the same committee. Sessions previously offered to resign because of tensions with Trump over his recusal decision.
Russian Federation has denied repeatedly that it interfered in the USA election, and Trump has denied any collusion by his campaign with Moscow. Ron Wyden, D-Ore., suggested the attorney general was ducking questions, angering Sessions.
Sessions hedged nearly all of his answers about whether/when he met with Russians, or why he was involved in firing Comey, or how he feels about the president's decisions, with: "I don't recall" or "I believe so" or "maybe". Richard Burr, the chairman of the Senate Intelligence Committee, subsequently turned the floor over to the attorney general, who went on to say that he had consulted with senior Justice Department staff prior to his testimony about what he called a "longstanding policy" regarding communications with the president.
"It would be premature for me to deny the president a full and intelligent choice about executive privilege", he said. "And when asked I said that to the president".
Vice-Chairman Mark Warner, a Democrat, emphasised that he was "concerned" the president did not realise the severity of the alleged threat from Russian interference in United States elections.
There's just one problem: Trump never invoked that right, known as "executive privilege" - a fact that Sessions himself admitted several times throughout the course of the hearing.
Testifying at a Senate hearing, Sessions said it was a "detestable and appalling lie" to suggest that he participated in or was aware of any collusion between Russian Federation and the Trump campaign.
Here's a look at the top quotes from Sessions' hearing.
Sen. Kamala D. Harris (D-Calif.) pressed Sessions to promise that he would at least provide documentation to help the committee's investigation, but Sessions allowed only that he would review Justice Department rules. He insisted that he recused himself from a single FBI investigation - the one into Russia's alleged ties to Trump's campaign - and that he did not think his recusal should block his ability to conduct oversight of the FBI and its director.
"Disappointed that AG Sessions is refusing to answer relevant and proper questions - Americans want truth", he said. Sessions did not take the remark well.
Harris was similarly reprimanded by Burr just six days ago for her manner of questioning Deputy Attorney General Rod Rosenstein.
Sessions insisted he has completely steered clear of anything having to do with the Russian Federation investigation. Trump cited the letter in firing Comey.
In March he acknowledged he met twice a year ago with Russia's ambassador to Washington, Sergei Kislyak.
Sessions' responses were equally aloof during an earlier portion of the hearing in which Senator Mike Warner, the panel's ranking Democrat, asked whether he had any knowledge of any discussions at DOJ about potentially pardoning Trump's associates. Comey, in his sworn testimony delivered to the committee, recalled addressing the attorney general after his uncomfortable private meetings with Trump.
He said he would agree to dismiss Mueller only if there were a legitimate basis to do so, and an order from the president would not necessarily qualify.
In his testimony last week, Comey said he and Trump had a one-on-one meeting in the Oval Office on February 14 about the investigation into the former national security adviser, Michael Flynn.
As Congress seeks to get to the bottom of Russian meddling in the 2016 elections, any potential Trump campaign collusion, and possible later attempts to shut down the related criminal investigation, the Trump administration's evasions are growing increasingly creative. "You are obstructing this Congressional investigation", he said.