The government of Mozambique has filed a case in the High Court in London against the investment bank Credit Suisse over what has become known as the "tuna bond" scandal.
Credit Suisse was one of the lenders that helped to arrange $2bn (£1.5bn) of government-backed loans that pushed Mozambique into a debt crisis.
Also named in the filing are three former Credit Suisse bankers, who have already been indicted in the US.
Credit Suisse declined to comment.
The court records said the case related to "commercial contracts", but gave no further details.
Mozambique's economy has been in crisis since 2016, when it emerged the country had more than $2bn of undisclosed state debts.
The loans, taken out between 2013 and 2016, were marketed as investments in schemes including maritime security projects and a state tuna fishery. But a proportion of the money has not been accounted for and the allegations made in the US indictment include accusations of kickbacks and fraud.
Manuel Chang, the former Mozambique finance minister who signed off on the loans, has been detained in South Africa since December on charges related to the loans scandal. He denies any wrongdoing.
The court documents filed in London also mention Surjan Singh, Andrew Pearse and Detelina Subeva, former employees of Credit Suisse who are waiting to hear whether they will be extradited to face charges in the US.
They are accused of conspiring to violate US anti-bribery law, as well as money-laundering and securities fraud, in an indictment issued by a US District Court in New York.