(Bloomberg) -- Two US lawmakers who visited a jailed Binance Holdings Ltd. executive in Nigeria said he is in poor health and asked the American embassy to seek a humanitarian release even as local authorities press on with a fraud trial against him. 

Representatives French Hill and Chrissy Houlahan said they used the opportunity of a national-security visit to the West African nation “to advocate for an American that has been wrongfully detained by the Nigerian government.”

Local authorities have held Tigran Gambaryan — the head of financial-crime compliance at Binance — since February on charges including illegal operations, currency manipulation and money laundering. They moved the US citizen to a prison in April. 

Nigeria’s tax agency dropped accusations of tax fraud against Gambaryan last week. A separate money-laundering case brought against him by the anti-graft agency resumed on Thursday in the capital, Abuja.

In a video posted on X, Arkansas Republican Hill said the Binance executive “has malaria and double pneumonia, and he reports that he has lost significant weight.” 

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In the same clip, Pennsylvania Democrat Houlahan said “we will be able to put the full force of America behind us to make sure that he is returned home safely.”  

Hill was among 16 Republican lawmakers that in a June 4 letter to President Joe Biden accused Nigeria of holding Gambaryan hostage. 

“We would like to state that these allegations are false and should be ignored," Nigeria's Minister of Information Mohammed Idris said in a statement on Friday. Gambaryan “is being held in lawful detention and has access to quality medical care whenever required."

The faceoff between Africa’s most-populous nation and the world’s largest cryptocurrency exchange burst into view in February, when Nigerian authorities detained Gambaryan and a colleague – who subsequently escaped – during a visit to discuss the company’s compliance issues with the country.

In an additional twist, Binance in May claimed that it was asked for a “secret” payment in cryptocurrency to make its problems in Nigeria “go away” — a suggestion that the authorities deny. The amount in question was $150 million, the New York Times reported separately, citing people it didn’t identify.

Authorities initially held the former US Internal Revenue Service officer at a guest house before Nigeria brought formal charges against him and Binance in April. Since then he’s been detained at the Kuje correctional center, a high-security prison in the city.

Binance’s problems in the West African nation had simmered for months prior to the detention, after authorities blocked access to cryptocurrency channels amid a clampdown on speculation against the local currency, the naira.

Officials say the platforms, which are very popular with Nigerians, have contributed to the local unit’s 68% drop against the dollar since foreign-exchange rules were eased in June last year.

Nigerian central bank Governor Olayemi Cardoso named the company during a Feb. 27 press conference after announcing a jumbo interest-rate hike to defend the naira. Decrying “illicit flows,” he said that $26 billion has passed through Binance in Nigeria “from sources and users who we cannot adequately identify.”

The Nigerian case is the firm’s latest legal problem. Its founder Changpeng Zhao was ordered on April 30 to spend four months in prison in the US for failures that allowed cybercriminals and terrorist groups to freely trade on its platform. 

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(Updates with statement from the Nigerian government in eight paragraph)

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