Justice Minister Eveline Widmer-Schlumpf has met Acting Deputy United States Attorney General David Margolis to discuss international financial issues.
The pair met on Monday in Washington before Widmer-Schlumpf held further talks on justice matters with US Attorney General Eric Holder, who has stepped aside from a US probe into Swiss bank, UBS, because of a conflict of interest.
The US Justice Department said Holder thanked Widmer-Schlumpf for Switzerland's offer for help with closing the Guantánamo Bay prison for terrorism suspects and the possibility of accepting detainees held at the facility.
They also discussed cooperation on fighting organised crime, terrorism and terrorist financing.
Holder, a former lawyer for UBS, has been said to be "embarrassed" by the tax fraud investigation into the bank.
US tax collectors issued UBS with a civil lawsuit last month seeking the identities of about 52,000 US clients who allegedly kept billions of dollars at the bank to dodge the Internal Revenue Service. UBS has said it will fight the case.