"You see, it's like this," said FIS press spokesman Boris Labusov.
Years of training at the FIS have instilled in agents the need to keep quiet about what they are up to.
But now, in a perhaps slightly more relaxed age, it turns out that after a hard day's work furthering the interests of the state, Russian agents like nothing better than the chance to exercise their vocal chords.
"You see, it's like this," said FIS press spokesman Boris Labusov.
"When our intelligence officers get together - and this is a rare opportunity for them - at some point they feel like a bit of a sing-song.
"And so they sing their favourite songs, including songs about their work written by professional and amateur songwriters. This idea was approved and supported by our leadership."
Anniversary
The songs include titles such as "This Difficult Job Called Spying," and "Profession: Espionage".
They are so popular, in fact, that the FIS has decided to issue a limited-edition CD and audio cassette to mark its 80th anniversary.
The CD has been issued on Chekist's Day, marking the anniversary of the founding of the Communist secret police service, the Cheka, in 1917.
In Soviet times, the day was a public holiday.
Limited edition
Russian NTV said the collection, called It's Tough To Be An Intelligence Agent, will not be available in the shops.
The songs will be distributed, perhaps on a need-to-know basis, by the association of Foreign Intelligence Service Veterans.
One of the songs - perhaps more likely to achieve cult status among its limited audience than reach a mass audience - warms the singers' hearts with the reassurance that as long as they are on the job, Russia is safe:
It's our job, or better still,
It's our life, our blood and sweat;
We're ready and waiting,
As soon as we hear the bugle calling us.
We travel on land
In the sky or by sea;
As long as intelligence work is being done,
The country is safe.
BBC Monitoring, based in Caversham in southern England, selects and translates information from radio, television, press, news agencies and the Internet from 150 countries in more than 70 languages.