Prince Charles laid a wreath at Piskarevskoye cemetery

Prince Charles attended a memorial ceremony on Monday at the Piskarevskoye cemetery near the encircled city, now renamed St Petersburg.

Between 1941 and 1944 the Germans launched a prolonged attempt to capture Russia's second city but never succeeded.

The Blokad, as the 900-day siege is known, left 670,000 dead, most of whom are buried at Piskarevskoye.

More than 180 slightly raised grassy mounds dotted with wild flowers contain the hundreds of thousands of remains of those who starved, froze to death or died from disease during the prolonged attack.

The mass graves are marked with single granite slabs at the end of each one, inscribed with the year and the red star symbol for soldiers and hammer and sickle for civilian casualties.

Eternal flame

A wreath was laid at a towering statue of a grieving Mother Russia, where Prince Charles paused with his head bowed.

The local band from the St Petersburg Garrison played the British National Anthem followed by the Russian equivalent.

Earlier, the prince stood in front of an eternal flame at the entrance to the site as a minute's silence was held for the dead.

Navy personnel from the Portsmouth-based HMS St Albans, which is in the country for Charles's visit, performed the role of the guard of honour.

The prince is on a three-day visit to Russia.

Working trip

After President Vladimir Putin's high profile state visit to Britain last month, Prince Charles' visit is very much a working trip, with his agenda is dominated by cultural and social issues, BBC royal correspondent Jennie Bond said.

The prince also visited SS Peter and Paul Cathedral to see the tombs of Russia's last tsar Nicholas II and his family.

Nicholas II, his wife, three of their daughters and servants were executed after the 1917 Bolshevik uprising.

Nicholas had been refused a safe haven in Britain by his cousin George V.

A sample of DNA from the Duke of Edinburgh, the prince's father, was used to help scientists and forensic experts establish whether the bones and skulls belonged to the Romanovs.

At noon Prince Charles fired the city's cannon, which has sounded every day since a similar gesture took place to signify the end of the Great Northern war in 1721.