Opposition to the White House pick to run Consumer Financial Protection Bureau escalated Tuesday when Democratic senators suggested the nominee may have been involved in the policy of separating children from their parents at the U.S. border.

Sens. Elizabeth Warren of Massachusetts and Sherrod Brown of Ohio, sent a letter Tuesday to Kathy Kraninger, seeking information on what role she played in the so-called zero-tolerance policy. Warren separately tweeted that she will place a hold on the nomination until Kraninger provides more details.

"Kathy Kraninger helps oversee the agencies that are ripping kids from their parents. Now @realDonaldTrump wants her to run the @CFPB. I will put a hold on her nomination – & fight it at every step – until she turns over all documents about her role in this," Warren said in the tweet.

Sen. Elizabeth Warren
On Kathy Kraninger, the nominee to run the CFPB, Sen. Elizabeth Warren said in a tweet: "I will put a hold on her nomination – & fight it at every step – until she turns over all documents." Bloomberg News

Kraninger is program associate director for general government programs at the Office of Management and Budget, with oversight of seven executive branch agencies, including the Department of Homeland Security and the Department of Justice. The Homeland Security and Justice departments developed "zero-tolerance policy" announced by Attorney General Jeff Sessions, a policy that Brown and Warren said has led to the "tearing away more than 2,000 children from the arms of their parents."

"The American people deserve to know what role you have played in developing and implementing this appalling process," Warren and Brown wrote in the letter.

In a press release, the senators noted that Kraninger is involved in "ongoing policy and management guidance," "implementation of policy options," and working with agencies on budgetary decisions related to legislation or administration policy.

The senators asked Kraninger to provide a complete description of any role she played in OMB budgetary or policy decisions, analyses or recommendations related to DOJ's "Zero-Tolerance" policy.

Kraninger would succeed former CFPB Director Richard Cordray, but now answers to Mick Mulvaney, who is serving a dual role as head of the Office of Management and Budget and acting head of the CFPB.

Mulvaney released a statement Tuesday with a ringing endorsement for the nominee.

"From navigating and interpreting how the federal government supports and regulates financial services for key stakeholders to helping stand up a brand-new federal agency when she was at the Department of Homeland Security in its earliest days, she has the kind of experience Washington so desperately needs," Mulvaney said in the statement. "I know that my efforts to rein in the bureaucracy at the Bureau of Consumer Financial Protection to make it more accountable, effective, and efficient will be continued under her able stewardship.”

Brown and Warren requested a list of meetings or phone calls Kraninger participated in and all emails and other documents involving communications with Justice Department, Homeland Security and the White House officials over the development and implementation of the zero-tolerance policy.