Sen. Chuck Grassley (R-IA), the chair of the Senate Judiciary Committee, is openly frustrated with the Trump administration dragging its feet on fully briefing Congress on its various Russia investigations.

This week, he put his foot down, refusing to move forward on the backlog of confirmation votes before his committee until FBI Director James Comey tells the committee what is going on.

“He was supposed to get back to us and we still haven’t heard anything,” Grassley vented to reporters in the basement of the Capitol Tuesday night. “So here’s what we’ve done: the Justice Department would like to get their deputy out of committee just as soon as they can. But I will not schedule a hearing on the Deputy Attorney General [Rod Rosenstein] until we get a briefing from Comey.”

Other members of the Judiciary Committee are speaking out as well, demanding information about the intelligence community’s probes into alleged Russian meddling in the 2016 election and contact with Michael Flynn and other members of the Trump campaign. The committee has also written to the FBI requesting evidence to back up President Trump’s seemingly baseless allegations that former President Obama wiretapped and surveilled him during the campaign. So far, they have received nothing.

Sen. Lindsay Graham (R-SC) told reporters Tuesday that he will exercise his subpoena powers if the committee continues to be stonewalled.

“We have jurisdiction over the FBI,” he said. “It wasn’t a complicated letter. This is not an unreasonable request. I expect some kind of reply.”