Former Special Counsel Robert Mueller asserted at the outset of his congressional testimony on Wednesday morning that he is bound by the Department of Justice to not discuss any ongoing matters or investigative information; and that he will not discuss the Steele Dossier.

“The Justice Department has asserted privileges concerning investigative information and decisions, ongoing matters within the Justice Department, and deliberations within our office,” Mueller said in his opening statement. “These are Justice Department privileges that I will respect. The Department has released the letter discussing the restrictions on my testimony.”

He added: “I therefore will not be able to answer questions about certain areas that I know are of public interest. For example, I am unable to address questions about the opening of the FBI’s Russia investigation, which occurred months before my appointment, or matters related to the so-called ‘Steele Dossier.’ These matters are the subject of ongoing review by the Department.”

The dossier, compiled by former British spy Christopher Steele, detailed President Trump’s ties to Russia and included a controversial accusation that Kremlin officials had a “pee tape” with which to blackmail the president. Trump has repeatedly attacked the dossier as part as what he has called a “hoax” against him.