KIEV, Dec. 27 - The Ukrainian currency, the hryvnia, may face significant downward pressure next year if Russia moves to steeply boost natural gas prices, a senior official at the National Bank of Ukraine said Tuesday.

The pressure may accelerate to a point that the NBU would be forced to let the hryvnia lose some of its value against the U.S. dollar, Anatoiy Shapovalov, NBU deputy governor, said.