As Poland joins Nato next year in the first wave of new members, the organisation will have an important new border with Russia.

Poland shares part of its northern frontier with the Russian region of Kaliningrad. Home to the Russian Baltic fleet, it remains strategically vital for Moscow.

But observers are warning that Russia's economic crisis left its Baltic outpost exposed - and a potential destabilising influence on Nato's doorstep.

For years the Baltiysk naval base was strictly off-limits to all but the elite of the Soviet military. It was the launch pad for a possible invasion of western Europe.

But with the end of Communism, it acquired a whole new significance. Ousted from its bases in the Baltic states and the Soviet satellites, the Baltic fleet concentrated its efforts and its firepower in Kaliningrad.

Strategic importance

It is the most westerly point of Russia. The naval base at Baltiysk was and is of vital strategic importance. That is set to grow, as Nato expands eastwards.

Home of Russia's Baltic fleet

The commander of the Baltic fleet, Vladimir Yegorov, says no-one should fear Russia's response if Nato expands to its borders.

But he says Kaliningrad is a special place that should be treated with respect.

"Kaliningrad is in a state of transition. You could say it is the military training ground for a new life," he said.

"Our region was always very important for Russia because of where it is and because of the ports and the infrastructure.

"Kaliningrad will always mean a lot to Russia."

Growing isolation

But Kaliningrad's isolation is growing. On the Lithuanian border, the main through-route to Moscow, the traffic is drying up.

Traffic on the Lithuanian border is drying up

The Lithuanian authorities impose high tariffs on transits from the Russian heartland. And the Russian financial crisis has drained Kaliningrad's resources.

It is dependent on its neighbours for food and fuel. Western advisers say it must loosen some ties to Moscow if it is ever to flourish.

"The only chance for the Kaliningrad region is to be open towards the European Union, to have a special status inside Russia but towards the EU," said German Economic Consul Stefan Stein.

"But I don't know if everybody in Moscow will understand this opinion."

Hong Kong of the Baltic

Russia's biggest car market is in Kaliningrad. Despite the general Russian financial crisis, trade is still lively.

Russian-German joint venture

Kaliningrad is already treated as a special economic area. It has been freed of customs duties and it was once touted as a Hong Kong of the Baltic.

But its status is dictated and limited by Moscow. And Kaliningrad's pro-Moscow lobby believes it must stay that way.

"Kaliningrad is like a special fortress in the west of Russia," says Communist deputy Yuri Dovzhenko.

"The population is here to protect Russian interests.

"We have to strengthen local Russian business, we don't want Kaliningrad to be used as a resource by the west."

Craving for stability

There are already joint Russian-European companies and observers say it is vital more foreign partnerships come to Kaliningrad and thrive.

Russia's biggest car market

They say Moscow is worried that wealth will encourage secession. But as the EU expands to surround it, they say Kaliningrad must look to the west to remain stable.

"The worst case scenario is a total economic and social collapse in this region, which will be a major destabilising influence within the entire Baltic rim," says Stephen Dewar of the EU support programme.

"It would have very threatening implications for the immediate neighbours Poland and Lithuania.

"It would also be extremely worrying and disturbing to the other Baltic rim countries, as well as to Nato," he says. "We are not talking about war, but a very unstable situation."

Kaliningrad has been a Russian region for only 50 years, but the Soviet planners have stamped their mark.