He also told a forum in the Italian town of Verona that there was a risk that OPEC may not have enough free oil production capacity to compensate for lower supplies from other producers hit by U.S. sanctions such as Iran or Venezuela.

Sechin also said the global oil sector needed a stable, significant inflow of investments in the long term to compensate for ageing oil-producing assets.

(Reporting by Oksana Kobzeva; Writing by Katya Golubkova; Editing by Susan Fenton)