MOSCOW - THOUSANDS of young Russians crammed into a Moscow square at dawn on Monday in a demonstration called by a pro-Kremlin youth group to keep alive the memory of Soviet heroism in World War II.

On the 68th anniversary of Nazi Germany's invasion of the Soviet Union, the controversial youth group Nashi (Us) bussed in activists from around the country to remember the sacrifices of their grandparents in the war.

The Kremlin has made remembrance of the Soviet victory over Nazi Germany a cornerstone of its thinking and has lashed out at what it says are attempts to deny the historical truth, especially by West-leaning ex-Communist states.

The participants held candles in a park at Sparrow Hills in western Moscow as dawn broke over the Moscow river below. They then went on to attach thousands of bells to trees to create an 'alley of memory.'

'They (the Soviet troops) were victorious. They went home then and they then rebuilt everything that was destroyed. They then sent a man into space. We thank you and we bow down low in front of you,' Nashi leader Nikita Borovikov declared in a speech.

Nashi - which emerged under Vladimir Putin's presidency and is clearly modelled on Communist-era youth groups - boasted that it mustered 15,000 people in the rally at 4.00 am (midnight GMT).

An AFP correspondent saw thousands of people crammed into the square in front of Moscow State University amid a heavy police presence. Dozens of buses that had brought them from provincial cities were lined up on the road.

Loudspeakers re-broadcast a famous Soviet radio broadcast that announced the pre-dawn invasion of German troops on June 22, 1941 at the start of Hitler's Operation Barbarossa, aimed at conquering the Soviet Union. -- AFP