U.S. Secretary of State John Kerry is in Bulgaria to press the NATO nation to wean itself from near-total dependence on Russia for energy.

Kerry arrived in Sofia on Wednesday and planned to explore ideas with Bulgarian officials for diversifying their energy supply. Among those ideas are the possible construction of a natural gas pipeline spur from Greece and moving ahead with a stalled contract with Westinghouse Electric Co. to build a nuclear power plant, according to U.S. officials.

Bulgaria relies on Russia for 85 percent of its gas and 100 percent of its nuclear power — rates among the highest in NATO. Russia's cancellation of the South Stream pipeline, which would have run under the Black Sea to Bulgaria, is making the need for diversification more acute.