Lithuania's plan to dock a floating liquefied natural gas terminal on the Baltic coast later this year played an important role in negotiating lower prices from Russian gas supplier OAO Gazprom, according to the nation's energy minister.

The Baltic nation is currently dependent on Gazprom for 100% of its natural gas, and Lithuanians have been paying 15% higher prices than the European average for gas. Concerns about price and energy security prompted Lithuania to lease a Norwegian-built ship—dubbed "Independence"—that...