Vladimir Putin has marked Christmas in Russia with a show of strength – by firing a huge cannon.

Under the Russian Orthodox liturgical calendar, Christmas is observed on January 7.

During a visit to his home town of St Petersburg, the Russian president visited the Petropavlovsky Fortress on the banks of the Neva River and pulled the lever on the howitzer, which fires a daily noontime salute.

Vladimir Putin prepares to fire the fortress cannon Credit: Alexei Druzhinin, Sputnik, Kremlin Pool Photo via AP

The midday shot has been a tradition since 1865.

Mr Putin’s steely image was in full force for the event – bareheaded in the winter cold, he appeared to flinch only slightly when the cannon roared, then turned away with a thin smile.

"Military fortress member of staff, I congratulate you, it was a wonderful cannon shot!" a fortress officer told him.