What does it take to reduce a former KGB spy with a black belt in judo to tears? Vladimir Putin, with his notorious tough-guy image, does not get sniffly very often. But it seems that a soft-rock song about the honour and bravery of the Russian police force did the trick.

At a concert in the Kremlin on Sunday, which is Police Day in Russia, Putin can be seen in the front row wiping a tear from his eye, his face twitching, as a song called You Know, I Really Want to Live is belted out by the band Rozhdestvo (Russian for Christmas).

Behind them, a large video screen runs a montage featuring heroic police officers and weeping relatives – the song is dedicated to officers who died in the line of duty. Putin is flanked by uniformed police generals and the audience is made up of serving policemen and veterans, who have come to listen to a number of Russian crooners and variety acts. Issues of corruption and brutality inside Russia's police force are not touched upon.

The audience listened to the song on their feet, with the whole hall apparently standing up following Putin's cue. The song was followed by a minute's silence, and the lead singer told a radio station afterwards that he had been told that Putin had started crying.

It is not the first time that Putin has cried in public. During a celebration rally after he was re-elected as president last May, Putin shed a tear as he addressed crowds of cheering supporters. His spokesman, Dmitry Peskov, later said that Putin had been affected by the icy winds rather than overcome by emotion.