Sigal Mandelker speaks during a Senate Banking Committee confirmation hearing on May 16. (Zach Gibson/Bloomberg News)

Leading Democratic senators are withholding votes for President Trump’s nominee to lead the Treasury Department’s terrorism and financial crimes division to protest the administration not producing records related to their probe of the Trump campaign’s alleged ties to Russian officials.

Top Senate Banking Committee Democrat Sherrod Brown (Ohio) and top Senate Intelligence Committee Democrat Mark R. Warner (Va.) complained during a committee confirmation vote for Sigal Mandelker that the administration is being too lackadaisical about producing documents that lawmakers have requested to supplement their probe into Russian meddling in the 2016 elections.

The Wall Street Journal reported earlier this month that the Treasury Department’s Financial Crimes Enforcement Network, better known as FinCEN, would share records with the Senate Intelligence Committee as part of its investigation. Warner and committee Chairman Richard Burr (R-N.C.) had sent a letter April 26 requesting documents, including alerts of possibly suspect transactions known as “flash notices” and information prepared in relation to terrorism or money laundering cases known as “314a requests.”

“While the committee has received some documents from Treasury, the information received thus far is insufficient, and we have expressed this concern,” Warner said Tuesday, following the vote to recommend Mandelker’s nomination to the full Senate. The vote was 16 to 7, with Warner, Brown and several other Democrats voting no — “a step I wouldn’t otherwise take,” Warner stressed, had the Treasury Department better complied with the request for information.

“What I can’t ascertain yet is, is this truly just slow-walking or is this just trying to fully understand the nature of our request,” Warner added to reporters after the vote.

Warner would not identify exactly what he hoped the FinCEN documents would reveal. But he noted that the committee is interested in seeing any evidence of “funds that may have flown into some of the Trump associates’ and Trump affiliates’ ” accounts and records related to former national security adviser Michael Flynn’s foreign income.

“This is an area that has not received much attention yet,” Warner said. “We want to leave no stone unturned.”

Several Banking Committee Democrats voting against Mandelker’s confirmation Tuesday said they hoped that the Treasury Department would furnish the requested documents before the full Senate took up the nomination.

Committee Chairman Mike Crapo (R-Idaho) said he would pass on their concerns to Republican Senate leaders.