Switzerland said on Thursday (Mar 17) it had frozen US$800 million during its investigation into corruption at Brazil's state oil firm Petrobras, but a portion of the funds had been returned.
The Swiss attorney general's office (OAG) previously put the amount of money blocked during the probe - which opened in April 2014 - at US$400 million.
The OAG statement said a total of US$190 million had so far been returned from Swiss banks to various individuals or entities.
The multi-billion-dollar Petrobras corruption scam has touched some of Brazil's most powerful figures, including President Dilma Rousseff and her predecessor Luiz Inacio Lula da Silva.
Rousseff's tottering government has been plunged deep into crisis, with the president fighting off new impeachment proceedings, mass protests, a deep recession and the splintering of her coalition.
Switzerland is probing evidence that huge portions of the funds scammed from Petrobras were funnelled to the federation's banks.
To date, Swiss prosecutors have opened 60 separate investigations into possible "aggravated money laundering", linked to Petrobras, involving 340 suspicious bank transactions.
Documents related to more than 1,000 accounts have been requested from over 40 banks, the OAG further said.
The owners of these accounts are "senior executives of Petrobras and ... its suppliers, financial intermediaries, Brazilian politicians," and various companies tied to Brazil, the statement said.