"What did we have?"
Bannon attempted to walk back from the remarks, telling the Axios news website that "Donald Trump Jr.is both a patriot and a good man", but the closest he came to an apology was regretting the timing of his response.
"I feel betrayed because you're not supposed to do that", Trump in an interview with the Wall Street Journal.
Cohen told WSJ that Trump denies "any such occurrence".
In "Fire and Fury", Bannon faulted Donald Jr., former campaign chairman Paul Manafort and Trump's adviser and son-in-law Jared Kushner for taking the meeting with the Russians during the presidential campaign and not reporting it to the Federal Bureau of Investigation.
Bannon's spectacular downfall is a significant setback and part of a larger pattern of reversals for Breitbart and the other far-right and fascist-tinged big business forces he represents.
Burck also said the representation only pertains to the Republican-led House investigation, and not special counsel Robert Mueller's independent probe.
Bannon on Sunday released a statement expressing regret over the comments.
A humiliating defeat for the Republican Party, the upset in Alabama's election was seen to signal the waning influence of Bannon's particular brand of populism, economic nationalism, and anti-immigrant rhetoric, which had resonated widely with the American public one year earlier during the presidential race.
President Donald Trump listens during a meeting with lawmakers on immigration policy in the Cabinet Room of the White House, Jan. 9, 2018, in Washington, D.C. But the scandals persecute Trump, and this debate was joined by the controversial tweet in which he claimed that the button for the launch of nuclear missiles in his office is much more powerful than the one claimed to have by the leader of the Democratic People's Republic of Korea, Kim Jong Un.
Bannon has agreed to an interview with the committee, which is investigating Russia's election meddling and links to the Trump campaign.