Opposition politicians and campaign groups in Senegal on Tuesday accused the government of secrecy after the BBC reported that a brother of the president had benefited from lucrative dealings in the gas sector.
The BBC report on Sunday, which the brother has denied, delved into contracts deriving from the discovery of major oil and gas reserves off the coast of the poor West African state.
It said that in 2012, newly-elected president Macky Sall confirmed a decision taken by his predecessor Abdoulaye Wade, to award exploitation rights for two fields to the Timis Corporation, controlled by an Australian-Romanian businessman, Frank Timis.
The BBC, in a report broadcast on its Panorama and Africa Eye programmes, said that two years later Timis Corporation secretly paid a "bonus" of USD 250,000 (222,000 euros) to Agritrans, a company controlled by Sall's younger brother, Aliou Sall.
Aliou Sall was also employed by the Timis group after his brother became president, receiving a salary of USD 25,000 per month, the BBC said.
He stepped down in October 2016 after being accused of a conflict of interest by the opposition. He was appointed head of a state-run savings deposit bank, the CDC, in 2017.
Aliou Sall on Monday denied the report, saying he would file suit against the BBC in Dakar and London for "libel."
A campaign group, Y'en a Marre ("Had Enough") said the BBC investigation "has once more revealed the opacity and lack of transparency surrounding negotiations and deals in these affairs."
It called on Aliou Sall to resign "and place himself at the disposal of justice."
"We are going to fight to recover control over our natural resources, our gas, our oil."