Story highlights Isabel Patelunas was nominated in June for an assistant Treasury secretary post

Oregon Sen. Ron Wyden has placed holds on nominees before

(CNN) Oregon Sen. Ron Wyden has placed a hold on a senior Treasury Department nominee in a bid to pry loose financial documents tied to Russia.

Wyden, the top Democrat on the Senate finance committee, said Friday he was placing a hold on Isabel Patelunas, President Donald Trump's nominee to be Treasury's assistant secretary for intelligence and analysis, until Treasury hands over the documents he's seeking.

"I have placed a hold on the nominee because of the Treasury Department's refusal to provide the Senate Finance Committee with Treasury documents related to Russia," Wyden said in a statement. "The provision of these documents to the committee is not only part of the oversight process, but is necessary if the relevant congressional expertise is to be brought to bear on the effort to follow the money."

Wyden wants documents from Treasury's Financial Crimes Enforcement Network (FinCEN), a unit that monitors global financing and frequently investigates money laundering.

The Treasury Department said that it had already responded to the request of a separate committee, the Senate intelligence committee, for FinCEN documents.

Read More