WASHINGTON (AP) – Attorney General William Barr is defending his handling of special counsel Robert Mueller’s Russia investigation report, saying the document contained sensitive grand jury material that prevented it from being immediately released to the public.

Barr’s statement Thursday came as he confronts concerns that his four-page letter summarizing Mueller’s conclusions unduly sanitized the full report in President Donald Trump’s favor, including on the key question of whether the president obstructed justice.

House Democrats on Wednesday approved subpoenas for Mueller’s entire report and any exhibits and other underlying evidence that the Justice Department might withhold.

The disparity in length between Barr’s letter and Mueller’s full report, which totals nearly 400 pages, raises the likelihood of additional significant information that was put forward by the special counsel’s office but not immediately shared.