Portugals BPI bank on Thursday ceded control of Angolas top lender to a telecoms company run by Isabel dos Santos, daughter of the countrys president and dubbed Africas richest woman.

After months of pressure from the European Central Bank to give up its majority stake in line with a tightening of rules, BPI sold two percent of the Banco de Fomento Angola (BFA) to Angola's largest phone operator Unitel to bring its stake down to 48.1 percent.

Unitel -- run by the daughter of President Jose Eduardo dos Santos -- now holds a controlling stake of 51.9 percent of the leading bank in oil and diamond-rich Angola, a former Portuguese colony.

The 28 million euro ($29.7 million) sale of the two-percent stake allows BPI to reduce its exposure to Angolan government debt, which the ECB deemed too risky under new European banking laws that came into force in 2015.

The central bank gave BPI until April 10 last year to reduce its risks, before allowing a delay.

Smaller shareholders in BPI had previously complained that the sale of the two percent stake unfairly benefitted Dos Santos due to her large interests in both BPI and Unitel.

The sale to Unitel has been seen as a means of securing Dos Santos' backing for a bid by CaixaBank, Spain's largest bank, to take over BPI.

CaixaBank has for months been trying to work out a deal with Dos Santos, who owns an 18.6 percent stake in BPI, to move the takeover bid forward.