BUCHAREST (Reuters) - Romanian prosecutors raided employees' homes and the Romanian unit of Serbian NIS Petrol, controlled by Russia's Gazprom Neft, and have opened a criminal investigation into allegations of confidential data leaks, the prosecutors said.

Contacted by Reuters, the company did not immediately respond and Gazprom Neft referred Reuters to NIS Petrol for comment.

Anti-organised crime prosecutors said in a statement late on Monday they raided the company's offices and nine employees' homes in the capital Bucharest and the western Romanian city of Timisoara in a case that concerns "divulging secret information and the unauthorised transfer of digital data".

After questioning eight people, the prosecutors said four Nis Petrol employees were under criminal investigation for allegedly failing to comply with Romania's fuels law and the national agency for mineral resources' (ANRM) regulations.

They also alleged they sent non-public data about mineral reserves to their Serbian mother company.

The statement did not say whether those under investigation had been detained.

NIS Petrol holds oil and gas exploration and extraction concession rights in Romania and operates a network of petrol stations in the western part of the country under the Gazprom brand.

(Reporting by Luiza Ilie; editing by Barbara Lewis)