The government of Chad and CEFC China Energy have both denied involvement in bribes that US authorities allege were offered to Chad’s president through Patrick Ho Chi-ping, former home secretary of Hong Kong and head of a non-governmental organisation funded by the Chinese energy conglomerate.

Mr Ho and former Senegal foreign minister Cheikh Gadio were arrested and charged in the US this week with violations of the Foreign Corrupt Practices Act, international money laundering and conspiracy to commit both.

A statement from US authorities released late on Tuesday described two schemes, the first of which allegedly saw Mr Gadio assist Mr Ho in causing a Chinese energy conglomerate to offer a $2m bribe — characterised as a “donation” for charitable causes — to Idriss Déby, the president of Chad.