"Today Nord Stream shareholders considered a preliminary feasibility study for the third and fourth legs.
RIA Novosti reported the company expects to sign memorandums of intention on the third and fourth legs by the end of the year.
"Before Dec. 31, it is planned to sign a memorandum on the construction of new capacities. One of the branches may go to Great Britain. We see interest from British partners," Miller said at the an event celebrating the launch of the second leg of Nord Stream.
The second leg of the natural gas delivery system is 775 miles long and connects the system to the Yuzhno-Russkoye gas fields in northern Russia's Yamal Peninsula.
The first leg connects the gas fields to Greifswald, Germany.
For most of its first year of service, however, the pipeline to Germany has only run at about 35 percent of capacity as the European economy has been in a prolonged slump.
Deutsche Bank analyst Josef Auer said the second leg of the project will continue to be underutilized until Russian gas prices come down to the level of other suppliers.
But the Nord Stream route offers European customers a second option for importing Russian natural gas. In recent years, disputes between Gazprom and Ukraine have prompted shutdowns of natural gas traveling through Ukraine, which has cut off supplies, on occasion causing midwinter hardships to customers in Europe.