By Sergio Goncalves and Catarina Demony
LISBON (Reuters) - The presidents of Angola and Congo said on Sunday Isabel dos Santos, the billionaire daughter of Angola's previous leader, and her Congolese husband Sindika Dokolo should cooperate with the justice system after their assets were frozen.
In a statement, the presidents said the best way forward for dos Santos and Dokolo, as well as Mario Leite da Silva, chairman of Banco de Fomento Angola (BFA), was "maximum cooperation with the competent authorities of the state and the Angolan court".
They did not immediately react to the presidents' comments.
Angolan President Joao Lourenco and Democratic Republic of Congo President Felix Antoine Tshisekedi Tshilombo met on Sunday in the Angolan city of Benguela, the statement said.
Since ending Jose Eduardo dos Santos' near 40-year grip on power in 2017, Lourenco has tried to erase the influence of his predecessor and reform sub-Saharan Africa's third-largest economy.
But Lourenco is under pressure as the economy continues to contract under his watch.
A court document dated Dec. 23 said the government believed dos Santos, Dokolo and Silva had caused the state losses of more than $1 billion.
The asset freeze applies to personal bank accounts of dos Santos, Dokolo and da Silva in Angola and stakes they hold in Angolan firms including Unitel, BFA and ZAP MIDIA.
Dos Santos and her husband have denied the accusations, calling them "politically motivated". Silva has declined to comment.
Called Africa's wealthiest woman, Isabel dos Santos has amassed a fortune estimated at more than $2 billion through stakes in Angolan companies including banks and the telecoms firm Unitel, earning her the nickname "the Princess".
She chaired the state oil company Sonangol before being sacked by Lourenco months after he came to power.
Last week, Bank of Portugal told Reuters it was evaluating dos Santos' suitability as a shareholder of Portuguese banks.
Dos Santos holds significant stakes in several important Portuguese firms, including Eurobic bank, telecoms company NOS and engineering company Efacec. She is also a shareholder in oil and gas company Galp Energia.
The asset freeze against her comes as the ex-president's son, Jose Filomeno de Sousa, faces corruption charges, accused of helping transfer $500 million from the sovereign wealth fund.
In the same statement, Lourenco called for "international cooperation to support the effort to combat corruption and impunity in Angola", adding the country had the legitimacy to trigger legal and diplomatic mechanisms to ensure the return of financial assets "illegally placed abroad".
(Reporting by Sergio Goncalves and Catarina Demony; editing by David Evans)