By Spencer Feingold

Updated at 6:13 p.m. ET

Attorney General William Barr defended his characterization of the Mueller report before lawmakers on Wednesday, just hours after a letter was released from the special counsel that stated Barr’s four-page summary of the report failed to capture its findings.

“I wasn’t hiding the ball on where Mueller was,” Barr told the Senate Judiciary Committee.

In a letter addressed to Barr, Mueller said the summary released on March 24 “did not fully capture the context, nature, and substance” of the special counsel's “work and conclusions.” The letter, which was dated March 27, also criticized the summary for creating “public confusion about critical aspects of the results of our investigation.”

Mueller’s letter was first reported on Tuesday evening and made public by the Justice Department Wednesday morning. The special counsel’s office had also contacted the Justice Department on March 25 to express concern about Barr’s summary, according to The New York Times.

Barr’s conduct in handling the report has lead several lawmakers to question the Attorney General’s independence from the Trump administration. In December 2018, President Trump nominated Barr to head the Justice Department after Attorney General Jeff Sessions resigned under pressure from the president.

“I think the American public has seen quite well that you are biased in this situation and you have not been objective,” Sen. Kamala Harris (D-Calif.), a 2020 presidential candidate, told the Attorney General.

Barr defended his summary saying the “body politic was in a high state of agitation” and he felt pressure to release “some information about the bottom line.”

While noting that no criminal conspiracy was established between Russia and the Trump campaign, Barr’s summary downplayed the points of the contacts between the two parties and said there was no conclusion on possible obstruction of justice by President Trump, which led the president to falsely declare total vindication in the Russian interference probe.

The full redacted report later illustrated several potential examples of obstruction and explicitly stated Trump was not exonerated.

“We saw why Mueller was concerned,” Sen. Dianne Feinstein (D-Calif.), the committee’s ranking Democrat, said in the hearing. The “March letter to Congress and the April press conference left the impression there were no remaining questions to examine, this report notes several limitations Mueller faced while gathering the facts that Congress needed to examine."

Republicans on the committee largely focused their questions on the origins of the special counsel's investigation and whether Trump has been falsely accused of colluding with a foreign power.

“This committee is going to look long and hard at how this all started,” Sen. Lindsey Graham (R-S.C.), the committee’s chairman, said. Sen. John Kennedy (R-La.) also called on the FBI to investigate the Russia probe and return to the Senate with answers.

In another point of contention, Democrats questioned Barr on his April 10 testimony in which he told Sen. Chris Van Hollen (D-Md.) that he did not “know whether Bob Mueller supported” his summary conclusion. Van Hollen, along with prominent Democrats like Sen. Elizabeth Warren (D-Mass.) and Rep. Eliot Engel (D-N.Y.), called on Barr to resign for lying to Congress.

Follow Wednesday's hearing, Sen. Harris also called on Barr to step down. "What I just saw from the Attorney General is unacceptable. Barr must resign now," she said in a tweet.

Barr was scheduled to testify on Thursday before the House Judiciary Committee but says he will skip the proceedings over objections to the testimony format, which would allow House lawyers to question him.

"If good faith negotiations don't result in a pledge of compliance in the next day or two, the next step is seeking a contempt citation against the Attorney General," Rep. Jerrold Nadler (D-N.Y.), the committee’s chairman, said if Barr refuses a subpoena.

"Committee staff questioning has long been an important, if underutilized, aspect of Congressional oversight that is in accordance with House rules and past precedent,” Rep. Nadler said in a statement Wednesday. “And no witness can simply dictate to this Committee the manner in which he or she is questioned when it is fully in accordance with House rules.”