Turkish authorities have arrested seven people, including a former central bank deputy governor and executives at the Interbank Card Center (BKM), under an investigation into alleged irregularities in tenders, a state prosecutor's office said on Friday.

The Istanbul chief prosecutor's office said its probe focused on irregularities in public tenders conducted by BKM, a key institution in Türkiye's payment systems, in which the central bank is the main shareholder.

Those now in custody include former Central Bank of the Republic of Türkiye (CBRT) Deputy Governor Emrah Şener and a former BKM general manager, the prosecutor's statement said, adding that detention warrants were requested for four further suspects who are currently abroad.

Şener denied involvement in such tenders, local media reported.

The Turkish central bank said it carried out an audit of the BKM in 2024 and as this triggered suspicions of an offence the bank filed a criminal complaint to the Istanbul chief prosecutor's office in December.

"The CBRT and the BKM are meticulously monitoring the ongoing judicial proceedings pertaining to the matter," the bank said in a statement on Friday.

Prosecutors allege that the suspects rigged bids, embezzled funds and committed fraud, resulting in public losses exceeding TL 100 million ($2.4 million), local media reported.