A shutdown of a natural gas pipeline would interrupt the flow of gas to Kaliningrad, part of the Russian republic west of Lithuania.
Kaliningrad remains a closed region within the Soviet Union, presumably because it has a number of strategic naval bases on the Baltic coast.
Kaliningrad has become one of the great arms bazaars in a region awash with military equipment and demoralised soldiers. The most worrisome scenario remains the prospect of a destabilising wave of economic refugees.
Soviet officials at the Soviet Mission Control Center in Kaliningrad, north of Moscow, tried to minimize the problem.
But if Moscow shut off natural gas, it would also cut off the Russian district of Kaliningrad, served by the same pipeline.
About one-third of modern Poland was in Hitler's Third Reich. East Prussia became part of the Soviet Union and now is called Kaliningrad.
It is an abnormal situation but controllable," said Vsyeva Latyshev, a spokesman at the Soviet Mission Control Center in Kaliningrad, north of Moscow.
Since 1992 it has jointly operated a network in Kaliningrad.
But it is adamant that it has no ulterior motives. Mr Yuri Matochkin, the head of the Kaliningrad regional administration, is clearly hedging his bets.
Foreign Ministry spokesman Gennady I. Gerasimov told journalists covering Soviet President Mikhail S. Gorbachev's visit to Bonn that one proposal calls for establishing an ethnic German region in Kaliningrad.
Soviet military officials are concerned by the refusal of Lithuanian youths to serve in the Soviet Armed Forces, and by prospects they would lose access to the Baltic ports of Klaipeda and Kaliningrad, accessible by land only across Lithuanian territory.