(CNN) During closed-door testimony that stretched roughly nine hours Tuesday, White House communications director Hope Hicks was pressed about whether she had ever lied for President Donald Trump -- and acknowledged she has had to tell what amounted to white lies, according to a source with direct knowledge of her testimony.

But Hicks argued that she hasn't had to lie about substantive issues for Trump, the source said.

Hicks, however, would not answer questions about her time in the White House during her House Intelligence Committee testimony as part of the panel's Russia investigation, though she did answer some questions about the presidential transition, according to lawmakers on the committee.

The New York Times first reported that Hicks admitted to white lies on the President's behalf.

Hicks is the latest senior official in the Trump orbit to decline to address questions about events that occurred after the 2016 election, as former White House chief strategist Steve Bannon and former Trump campaign manager Corey Lewandowski have made similar claims during testimony before the House panel.

Hicks' testimony was more forthcoming than that of Bannon -- who would answer questions only about the campaign -- but Democrats said she failed to answer key questions by walling off her time at the White House, arguing that other administration officials did not take a broad view about what they could not discuss.

House Intelligence Committee ranking member Adam Schiff said Hicks would not discuss, for instance, her role in drafting the misleading statement from Donald Trump Jr. about the June 2016 Trump Tower meeting with a Russian lawyer.

"All of our questions about what went into that statement went unanswered," the California Democrat said.

Hicks did tell the committee that the first time she learned about the Trump Tower meeting was in June 2017, three sources familiar with the matter told CNN. While she was in Trump Tower that day in June 2016, Hicks said, she did not have any awareness that the meeting took place, the sources said.

Initially Hicks told the committee she would not discuss the transition at all, citing a White House request, according to lawmakers. But she then agreed to answer some questions about the transition after conferring with the White House, because she had answered them previously before the Senate Intelligence Committee -- although Schiff said there were transition questions not asked by the Senate that she still would not address.

Schiff said Democrats pushed for the committee to subpoena Hicks "on the spot" to compel her testimony, but Republicans did not agree to do so.

Hicks did not invoke executive privilege, but she said she had been instructed by the White House not to answer the questions, Schiff said.

When Bannon appeared before the committee last month and didn't answer questions beyond the 2016 campaign, he was hit with a subpoena during the interview. Republicans said Bannon's claim that he could invoke executive privilege during the presidential transition did not have merit.

"There's apparently one rule for Steve Bannon and another rule for everyone else," Schiff said.

But Republicans said Hicks was a different case because she was willing to answer some questions about the transition.

"Mr. Bannon was claiming a privilege based on the transition that we were asking what the privilege was and we weren't comfortable that there was such a privilege," said Rep. Tom Rooney, a Florida Republican. "Since she has decided to answer questions based on that transition, she cannot be compared to Mr. Bannon, so it's not the same."

Rep. Trey Gowdy, a South Carolina Republican, said his issue was more with the White House's stance on the transition period, rather than with Hicks.

Earlier on Tuesday, other Democrats on the committee were also pushing for the panel to subpoena Hicks for not responding to its questions.

"We got Bannon-ed," said Rep. Denny Heck, a Washington state Democrat.

"I have less hope we'll get to all the answers," said Rep. Mike Quigley, an Illinois Democrat. "As with anyone who doesn't answer questions, they ought to be subpoenaed."

Rep. Mike Conaway, the Texas Republican leading the House Intelligence Committee's Russia investigation, told CNN ahead of the meeting that he expected Hicks to answer all of the committee's questions. He declined to comment Tuesday afternoon on Hicks' testimony or a possible subpoena, saying he would wait until the interview had concluded.

Bannon returned to the committee under subpoena earlier this month to continue his testimony, and he told the panel he had been instructed by the White House to invoke executive privilege on behalf of Trump.

Schiff has called for Bannon to be held in contempt of Congress for refusing to answer questions, as well as Lewandowski, who also limited the scope of questions he would answer. Conaway said Tuesday that he has to discuss the matter with House Speaker Paul Ryan before deciding how to proceed.

Quigley said Hicks had not asserted privilege Tuesday, but she was "following the orders of the White House not to answer certain questions."

Hicks did not answer reporters' questions on her way into the interview Tuesday morning. She was initially scheduled to appear before the committee last month as part of the panel's investigation into Russian meddling in the US election, but her interview was delayed over questions about the scope of her testimony.

Hicks, a trusted Trump aide for years, was one of then-candidate Trump's first hires as he put together an improbable run for the White House. During the campaign, she was often by Trump's side and attended nearly every rally, while she was in frequent communication with other senior officials as they coordinated their tactics to win the White House.

The House panel planned to interview her about any knowledge she has of contacts that occurred between other Trump associates and Russians.

Hicks appears to have firsthand knowledge of a number of key events that have shaped the first year of the Trump White House, including being on Air Force One when the initial misleading statement about Trump Jr.'s meeting with Russians was crafted.

This story has been updated with developments from Tuesday.