Steve Bannon was subpoenaed to answer questions in Russia probe

Jan. 16 (UPI) -- Former White House strategist Steve Bannon testified before the House Intelligence Committee Tuesday as part of the ongoing Russia probe.

Bannon was subpoenaed by Robert Mueller, the special counsel leading the probe, after he said the White House told him not to answer questions. The New York Times reported that it was the first time Mueller used a grand jury subpoena on a member of Trump's inner circle, many of whom have already been questioned as part of the investigation.

The House Intelligence Committee questioned Bannon for eight hours.

Bannon's testimony was set for a closed session -- marking his first appearance since he resigned as the executive chairman of Breitbart News earlier this month.

The meeting Tuesday also came after the release of Michael Wolff's controversial book Fire and Fury: Inside the Trump White House.

In the book, Bannon is quoted as calling a meeting between a Russian lawyer and Donald Trump Jr., son-in-law Jared Kushner and then-campaign chairman Paul Manafort "treasonous" and "unpatriotic."

President Donald Trump publicly criticized Bannon for his comments, saying the former strategist had "lost his mind."

The House committee is also expected to question White House Communications Director Hope Hicks.

Hicks was named communications chief in September after Anthony Scaramucci left the position.

Former federal prosecutor Joyce Vance told NBC News Hicks could serve as a potential "crown jewel" to the investigation because she has been involved with Trump's communications team for so long.

Her appearance could come as early as this week.