Romanian authorities have searched the offices of NIS Petrol, a Serbian oil company owned by Russian energy giant Gazprom, as part of an investigation into the dissemination of classified information.
According to the Office of the Public Prosecutor, the searches took place in the capital, Bucharest, and in Timisoara.
The Directorate of Investigations into Organised Crime and Terrorism said eight NIS Petrol employees had been questioned.
According to the Prosecutor's Office, four are under investigation but have been released. The four are suspected of passing on secret reports about oil fields to the parent company in Belgrade. The Prosecutor's Office also mentioned "the illegal transfer of computer data."
NIS Petrol has been active for many years in Romania, one of the largest producers of oil and gas in the European Union. It has a concession comprising six gas and oil fields in the regions of Bihor and Timisoara, near the Serbian border. The company also operates 19 Gazprom service stations in Romania.
The former state-owned company was partly privatised in the 2000s: Gazprom then became the majority shareholder. The Serbian state still owns nearly 30% of NIS Petrol's shares.
Serbian President Aleksandar Vucic has denied any Serbian involvement as tensions over energy run high in Europe. Belgrade has condemned the invasion of Ukraine at the UN but refuses to join the Western sanctions against Moscow.
