South African telecoms giant MTN has denied illegally moving $13.92 billion out of Nigeria.

The Nigerian Senate resolved on Tuesday to investigate the allegation that MTN, Africa’s biggest telecoms company, illegally transferred the money out of the country.

The resolution followed a motion moved by Sen. Dino Melaye (APC-Kogi) who relied on a point of order to make the allegations.

Melaye had fingered Nigeria’s minister for trade and investment Okechukwu Enelamah as one of the conduits for the illegal transfer that was carried out in 2008.

But MTN insisted that it has done nothing wrong.

 “The allegations made against MTN are completely unfounded and without any merit,” MTN Nigeria chief executive Ferdi Moolman said in brief statement on Wednesday.

The allegation threatens to raise tensions between Nigeria and MTN just three months after the South African firm agreed to pay a reduced fine of 330 billion naira in a settlement with Abuja over unregistered SIM cards.

MTN is the largest mobile phone operator in Nigeria, which accounts for around one third of the company’s revenues. The company had threatened to pull out of Nigeria during the dispute over unregistered SIM cards.