Saudi Arabia energy minister Prince Abdulaziz bin Salman held talks with Russian Deputy Prime Minister Alexander Novak at the St Petersburg economic forum in Russia on Thursday, a Reuters witness said.
The two men were seen entering a meeting room on Thursday morning.
The Saudi Arabia energy minister was not listed as an official guest at the forum.
Russian oil and fuel revenue up even as exports fall: IEA
Many other traditional Russian partners stayed away from the annual event.