U.S. Senator Maria Cantwell (D-WA) is calling for an independent special prosecutor to lead any investigation on the Trump campaign’s contact with Russian officials.

Cantwell noted Thursday that U.S. Attorney General Jeff Sessions should have disclosed his contacts with Russian officials during his Senate confirmation hearing, and said, “There are still too many questions left unanswered”

In response to the news this week that Sessions had failed to disclose two meetings he had taken with Russian officials during the 2016 presidential campaign, Cantwell released the following statement:

“After his contact with Russian officials during the Trump campaign, it’s only appropriate that Attorney General Sessions recuse himself from these investigations; however, I am troubled by the timing of his decision.

“Why did it take allegations of wrong-doing for him to come to this decision rather than disclosing these meetings during his confirmation hearings?

“There are still too many questions left unanswered regarding the extent of Russian interference in the campaign. It’s time to appoint an independent special prosecutor to conduct the investigation. It is not acceptable to think someone under the direct supervision of the Attorney General could do this investigation. The American people deserve answers about the contacts between those involved with the Trump campaign and Russian intelligence officers and government officials. We must get to the bottom of this issue to ensure the integrity of our elections and our democracy.”

Sessions announced Thursday he would recuse himself from any investigation into the presidential campaigns, including contacts between the Trump campaign and Russian officials and operatives, amid public pressure this week that intensified after news reports of Sessions’ meeting with Russian officials.