More than 50 world leaders will join President Vladimir Putin in Red Square tomorrow for a huge military parade, featuring second world war tanks, aircraft and veterans, to honour the USSR's victory over Nazi Germany 60 years ago. But controversy is sure to rage on the sidelines, with some eastern European leaders demanding Russia apologise for 50 years of post-war Soviet domination. And some Russian war veterans say they may take the occasion to protest against their shrinking pensions and social benefits, under reforms introduced by Mr Putin this year. 'For the Kremlin, it is a difficult anniversary to manage. There are a lot of discordant voices,' says Sergei Kazyonnov, an expert with the Institute of National Security and Strategic Research in Moscow. 'But Putin will be hoping to get political dividends from this. It looks like the world is coming to him.' The 56 leaders who will attend what Mr Putin has billed as a day to celebrate 'the joy of victory and reconciliation' include heads of the three main defeated powers of the war - Germany, Japan and Italy - as well as many of the USSR's key allies in the conflict. President Hu Jintao will be on hand, as will US President George W.Bush, French President Jacques Chirac and Indian Prime Minister Manmohan Singh. Western leaders might feel uncomfortable sharing the reviewing stand with some Kremlin guests, such as Belarusian dictator Alexander Lukashenko, Turkmenistan's despotic president-for-life Saparmurat Niyazov and Wojciech Jaruzelski, the Polish general who imposed martial law on his country at Moscow's behest in the 1980s. The Russian public will have to watch the event on television. Officials have announced that Moscow's downtown core will be sealed off by 30,000 police, with orders to admit only accredited guests. Only a handful of Russia's 1 million surviving war veterans were invited to take part in the Soviet-style military parade, which will include a massive display of tanks, missiles, artillery and a fly-by of vintage fighter planes. Some veterans say they have not forgiven the Kremlin for slashing their benefits and will find their own ways to protest on Victory Day. 'We are very angry, and nothing Putin is doing has improved our mood,' says Maria Rokhlina, 84, who fought at the Battle of Stalingrad and today leads a Moscow veterans' association. 'The people who fought for this country are left to live on a pittance. We've been humiliated,' she says. Twenty-seven million Soviets died in what Russians still call the Great Patriotic War. Most of the western USSR was destroyed as vast Nazi and Soviet armies surged across it in the titanic four-year struggle that ended when the Red Army stormed into Berlin. Nearly eight in 10 of all living Russians is descended from a war veteran, and Victory Day remains the only Soviet-era holiday that is universally honoured. Some Russian intellectuals and cultural figures complain the Kremlin has permitted the 'virtual rehabilitation' of wartime leader Joseph Stalin in the run-up to Victory Day. The dictator is blamed for millions of deaths during the collectivisation of agriculture and political terror of the 1930s, and also for costly military blunders when the Nazis invaded the USSR in 1941. Mr Putin has sanctioned a line of commemorative coins bearing Stalin's profile, and at least two Russian cities have said they will erect statues to him. A huge bronze bust depicting three wartime leaders - Stalin, Winston Churchill and Franklin Roosevelt - will be put up in Volgograd this week amid appeals by local residents to return to the city's wartime name of Stalingrad. 'For the first time since Stalin's crimes against humanity were exposed, there is an effort in our country to erect a monument to him,' said a letter in the daily Izvestia, signed by 20 leading Russian intellectuals. The fact that the statue will include other leaders 'is a transparent trick to cover up this blasphemous tribute to Stalin', it says. Polls show that about a third of Russians regard Stalin as a great leader who brought order and national glory to Russia, but a similar number believe he was a bloody tyrant. 'A lot of Russians still long for a strong hand and so they admire Stalin,' says Mr Kazyonnov. 'Everyone takes what they want from history.' A serious source of tension that will be conveyed by many of the foreign guests invited to Red Square concerns the pre-war deal between Stalin and Adolf Hitler that divided central Europe between them and gave Germany a green light to invade Poland in 1939. After the war the USSR incorporated the territories granted it under the Hitler-Stalin Pact, including eastern Poland, the Baltic states and Moldova. Leaders of two Baltic states, Estonia and Lithuania, are boycotting tomorrow's Red Square celebration on the grounds that the Soviet victory did not spell liberation for them, but another half-century of communist rule. The third Baltic president, Latvia's Vaira Vike-Freiberga, agreed to come to Moscow but said she would use the occasion to urge Mr Putin to repudiate the Hitler-Stalin deal. The European Union, which last year admitted the Baltic states, will also press Moscow on the issue at a Russia-EU summit in Moscow on Tuesday. 'We have to testify that the end of the second world war was a day when fascism was defeated and it was a victory day, but not for everybody,' EU official Guenter Verheugen said last week. 'For the Baltic states it was the beginning of dictatorship, violation of human rights, denial of democracy and self-determination,' he said. But Russia's representative to the European Union, Sergei Yastrzhemsky, said the issue could disrupt the Victory Day celebration. 'One cannot use the term occupation to describe those historical events,' he said last week. 'The troop deployment took place ... with the clearly expressed agreement of the existing authorities in the Baltic republics.' Russian experts say Mr Putin's main purpose in organising the Red Square party may be to bolster his flagging political fortunes by basking in the reflected light of the USSR's greatest moment. 'Many people say that the Soviet victory over Nazism is the chief remaining source of legitimacy for the Russian state, which faces many troubles today,' says Sviatoslav Kaspe, director of the Russian Public Policy Centre, an independent think-tank. 'So, it's not surprising that the Kremlin is highlighting Victory Day. But, if that's the main thing we have, it makes one feel quite uneasy.'