Binance Holdings Ltd. said it was asked for a large payment in Nigeria to make problems there “go away,” and repeated calls for the release of its employee who’s been jailed in the West African nation.

Chief Executive Officer Richard Teng made the claim in a blog on Monday, detailing how the world’s largest cryptocurrency exchange tried to engage with Nigerian authorities, including a Jan. 8 meeting in Abuja, the capital, where it was confronted with criminal allegations.

“As our employees were leaving the venue, they were approached by unknown persons who suggested to them to make a payment in settlement of the allegations,” Teng wrote. The blog did not say if the individuals were from the Nigerian authorities.

Later that day, Binance’s local lawyer was “presented with a demand for a significant payment in cryptocurrency to be paid in secret within 48 hours to make these issues go away,” Teng wrote. The amount in question was $150 million, the New York Times reported separately, citing people it didn’t identify.

Nigeria, which blames crypto speculators for some of the naira’s steep recent losses against the US dollar, disputed this account.

“Investigators are confident that the sequence of events is not as Binance has indicated, nor the material facts,” said Zakari Mijinyawa, spokesman for Nigeria’s National Security Adviser. “It will of course be for the courts to decide, and for due process to be followed and justice delivered.”

The incident marks the latest legal problems for Binance, whose founder Changpeng Zhao was ordered on May 1 to spend four months in prison in the US for failures that allowed cybercriminals and terrorist groups to freely trade on its platform. Binance in November agreed to pay $4.3 billion to resolve the US allegations.

In Nigeria, the confrontation led to the arrest of two of its staff after they returned in late February for further talks. One of them fled, but the other, Tigran Gambaryan, has been jailed at the Kuje correctional center in Abuja and will go on trial this month to face charges of tax evasion, currency speculation and money laundering.

Teng said Gambaryan and his colleague Nadeem Anjarwalla, who later escaped from custody, were given repeated assurances they would be granted safe passage.

“To invite a company’s mid-level employees for collaborative policy meetings, only to detain them, has set a dangerous new precedent for all companies worldwide,” he said.