ABUJA (Reuters) - Citigroup <C.N> has denied being involved in any illegal foreign currency transfer on behalf of MTN Group <MTNJ.J>, according to a presentation the U.S. bank gave to the Nigerian parliament.

Nigeria is investigating whether South African telecoms company MTN unlawfully repatriated $13.92 billion from Nigeria between 2006 and 2016.

"We wish to state categorically that Citibank Nigeria Limited was at no time involved in any illegal foreign currency repatriation on behalf of MTNN (MTN Nigeria) or any other customer," Citibank said in a presentation to parliament last week.

(Reporting by Camillus Eboh; Editing by Susan Fenton)