A US-educated former Goldman Sachs banker, with no formal diplomatic role at the time, Dmitriev cut an unexpected figure at the talks next to more conventional members of the Russian delegation such as foreign minister Sergei Lavrov.

Europe's participation in Ukraine peace talks will be needed eventually but Moscow first wants to build trust with Washington, President Vladimir Putin said on Monday, while suggesting that a deal to end the conflict may still be far off.

The meeting between the two countries' top diplomats in Riyadh is the most significant since Russia invaded its neighbor almost three years ago. It is meant to pave the way for a meeting between U.S.