The Swiss government has blocked assets belonging to Haiti's former ruler, Jean-Claude "Baby Doc" Duvalier, and his associates.
At the same time authorities have handed Belgrade bank documents liked to an investigation against three associates of the Yugoslavia's former president, Slobodan Milosevic.
Both cases emerged on Friday, and are being seen as further evidence of Switzerland's efforts to crack down on ill-gotten funds in Swiss bank accounts.
The cabinet on Friday announced it had re-affirmed an existing freeze on Swiss-held assets belonging to Duvalier worth SFr7.5 million ($4.8 million).
The funds were originally frozen in 1986, after a request by Haitian authorities when Duvalier fled from the Caribbean island.
Duvalier -said to be exiled in France - has long been accused of hiding a total of $130 million around the world, in gains from corruption and embezzlement.
At the time of his departure from Haiti, Switzerland was asked for legal assistance to help return the Swiss-held funds.
The new freeze was imposed after it emerged that the "provisional" 1986 block was about to expire for technical reasons.
Nicholas Michel, a senior official in the foreign ministry, said the Swiss government had spent 16 years repeatedly calling on Haiti to cooperate and provide the necessary documents to confirm the funds were illicit.
"We intervened several times to remind them that they had to act. But they have not been in a position to act which is consistent with international standards regarding human rights and justice," Michel told swissinfo.
No safe haven
Three years ago some of the funds, held in banks in Zurich, had to be unfrozen because the legal proceedings had ended.
Michel said the Swiss government was sending out a clear message by blocking the funds. He said Switzerland was not willing to serve as a safe haven for ill-gotten assets.
The foreign ministry said it was actively working with all parties concerned to find a solution to the Duvalier funds.
"We want to repatriate these assets as soon as we have proof that they are ill-gotten", Michel said.
The Duvalier case reflects the Swiss government's intervention in blocking assets of the former Philippines president, Ferdinand Marcos, and those of the former president of Zaire, Mobutu Sese Seko.
Belgrade legal assistance
The Swiss authorities on Friday also announced that they are granting legal assistance in a case linked to former president of Yugoslavia, Slobodan Milosevic.
The Federal Office of Justice said it handed over bank documents relating to an investigation by the Yugoslav government against Milosevic associates, suspected of illegally enriching themselves.
The Serbian finance minister, Bozidar Djelic, said on Saturday that according to the documents, nine of Milosevic's close associates put some SFr9 million ($6 million) in Swiss bank accounts during Milosevic's rule.
"Now it is up to our investigators and courts to complete the remaining pieces of the puzzle," Djelic said. "The Swiss have done their part."
While Swiss officials refused to reveal the identity of any of the bank account holders, Djelic said that an account allegedly belonging to the former Serbian prime minister, Mirko Marjanovic, held SFr1.25 million ($2.25 million).
A separate search for assets belonging to Milosevic and his family is continuing in Switzerland.
However, so far no funds attributed to the former Yugoslav president have been found, Swiss officials said.
The search was ordered in 1999 following a request from the United Nations War Crimes Tribunal in The Hague.
swissinfo with agencies