The EU's looming enlargement into eastern Europe ran up against its first big external obstacle yesterday, when Moscow and Brussels were deadlocked on how to deal with a Russian pocket that will be locked territorially inside the expanded union.  After 15 months of hard bargaining, a Russia-EU summit in Moscow disagreed fundamentally on freedom of movement for the people of the enclave when its neighbours, Lithuania and Poland, join the EU and end visa-free travel for Russians crossing their territory. Kaliningrad is bordered on three sides by the members-to-be and by the Baltic sea on the other.  Russia's president, Vladimir Putin, warned that the issue was one of principle and would determine the future of Moscow's relations with Brussels. But with immigration the hottest political topic in western Europe, the EU commission made it plain that Brussels would not relax its insistence on introducing EU visas for Russians travelling to and from Kaliningrad via Lithuania or Poland.  Mr Putin described the EU proposals as an affront to the "civilised community" and cast the dispute as a quarrel about basic human rights. "We don't have the right not to observe fundamental human rights there," he said after meeting the European commission president, Romano Prodi, and the Spanish prime minister, Jose Maria Aznar, current holder of the EU's presidency.  A senior EU source said: "There will have to be some movement, but that will have to come from the Russian side."  Mr Putin said Brussels had ignored Moscow's suggestions for resolving the dispute. "They are making proposals to us which essentially mean only one thing: (that) the right of Russians to free communication with relatives inside Russia will depend on the decisions of other states," he said.  His apparent strength of feeling may be reinforced by the fact that his wife, Lyudmila, is from Kaliningrad.  The pocket, with an estimated population of 900,000, is disease-ridden, criminalised and very poor. Much of its population depends on smuggling and cross-border trading. A bad situation will worsen when Lithuania and Poland join the EU within three years.  "Kaliningrad should not become a bone of contention between Russia and the enlarged EU," the EU's external affairs commissioner, Chris Patten, said last year as the talks got under way.  But both sides have dug in their heels. A fortnight ago the EU dismissed as unacceptable Russian proposals for special 160-mile rail and freight corridors through Lithuania linking Russia and Kaliningrad.  The Kaliningrad conundrum will be raised at the EU summit in Seville in a few weeks to see whether more flexibility can be introduced into the Brussels proposals.  But given the prominence of immigration issues in recent elections, and ahead of a German ballot in September, EU insiders said western Europe could not afford any breach in the Schengen rules - the system that enables free movement within most of the EU while reinforcing its external borders.  An EU official said that proposals for visa-free rail travel for Russians across Lithuania would result in Channel tunnel-type scenarios of illegal immigrants clinging to the trains to enter the EU.  Senior EU officials said Mr Putin was extremely tough yesterday on the issue, which contrasted graphically with the bonhomie of the past week's summits between Moscow, the US and Nato.  While those summits were long on the rhetoric of burying the cold war, the haggling about Kaliningrad recalls divided cold war Germany, with talk of transit agreements and new iron curtains.  Although Mr Prodi said the EU was about to recognise Russia as a market economy, he also raised Moscow's hackles by demanding energy price rises inside the country. In Brussels' view, the low cost of gas inside Russia amounts to an annual pounds 3bn subsidy to the country's industry.  Special report on Russia at guardian.co.uk/russia Classification Language: ENGLISH Subject: EUROPEAN UNION (92%); EUROPEAN UNION INSTITUTIONS (90%); EUROPEAN UNION ACCESSION (89%); PASSPORTS & VISAS (76%); IMMIGRATION (76%); INTERNATIONAL ECONOMIC ORGANIZATIONS (75%); ELECTIONS (74%); HEADS OF STATE & GOVERNMENT (74%); EU PRESIDENCY (73%); DISEASES & DISORDERS (71%); PRIME MINISTERS (68%); HUMAN RIGHTS (66%) Company: EUROPEAN COMMISSION (55%); EUROPEAN COMMISSION (55%) Organization: EUROPEAN COMMISSION (55%); EUROPEAN COMMISSION (55%); EUROPEAN COMMISSION (55%); EUROPEAN COMMISSION (55%) Person: VLADIMIR PUTIN (77%); ROMANO PRODI (54%) Geographic: MOSCOW, RUSSIAN FEDERATION (94%); BRUSSELS, BELGIUM (90%); ANDALUSIA, SPAIN (79%); ATLANTIC OCEAN (73%); BELGIUM (94%); LITHUANIA (94%); RUSSIAN FEDERATION (94%); EUROPE (94%); EUROPEAN UNION MEMBER STATES (94%); POLAND (92%); WESTERN EUROPE (92%); SPAIN (79%); GERMANY (79%); EASTERN EUROPE (58%)