The Swiss ambassador to Peru, Eric Martin, has denied reports that pressure from Washington prompted the Swiss to block some SFr90 million worth of funds belonging to the former spy chief, Vladimiro Montesinos.
The media in Peru attributed the recent move by the Swiss judicial authorities to pressure from the CIA and the American Drug Enforcement Agency, the DEA.
Martin denied this on Peruvian radio, RPP: "We did it of our own initiative, there was no external pressure on the Swiss authorities to intervene."
He said Switzerland decided to act after examining accounts linked to Montesinos, following banks' reports of suspected money laundering.
On October 5, three Swiss banking institutions - namely Leumi le-Israel, Crédit Agricole Indosuez and Fibi Bank - froze assets worth nearly SFr90 million.
Pascal Gossin, spokesman for the Swiss justice ministry, told swissinfo that Montesinos was the "beneficial owner" of some of the accounts, and the direct account holder of others.
Under Swiss law banks are required to disclose any suspicious transactions within five days to the authorities.
Gossin said the Swiss ambassador in Lima, Martin, recently informed the Peruvian government about the accounts and urged the Peruvian justice minister, Alberto Bustamante, to open an investigation into the affair.
Bustamante said neither he not the beleaguered president, Alberto Fujimori, were aware the accounts existed before the Swiss informed the government.
The case was made public just hours after Peru's Congress approved constitutional changes last Thursday to cut short Fujimori's presidency, clearing the way for elections to be held on April 8.
swissinfo with agencies