When one of the five journalists who interviewed him complained about federal investigators arriving to search the home of a witness in an inquiry early in the morning, Mr Medvedev told the journalist not to worry before stepping out of shot.
But his microphone was still switched on when he said casually: "They are just jerks, so they come at eight in the morning. It's just their set of habits. I know many people who work in the police. They think if they come at seven in the morning they will get everything in the world."
Another of the journalists asked whether the president is handed secret files on aliens when receiving the briefcase needed to activate Russia's nuclear arsenal.
"Along with the briefcase with nuclear codes, the president of the country is given a special 'top secret' folder. This folder in its entirety contains information about aliens who visited our planet," Mr Medvedev answered playfully.
"Along with this, you are given a report of the absolutely secret special service that exercises control over aliens on the territory of our country ... More detailed information on this topic you can get from a well-known movie called 'Men In Black' ... I will not tell you how many of them are among us because it may cause panic," he says.
None of the television stations that interviewed Mr Medvedev broadcast the off-air comments, but they were delivered to Reuters as a pool signal and some were shown on YouTube.