Igor Strelkov, a pro-Russian rebel commander, spoke to the media in the city of Donetsk, eastern Ukraine, on Monday. (AP Photo/Dmitry Lovetsky)

Pro-Russian separatist fighters are being warned to clean up their foul-mouthed language by local militia commander Igor Girkin, who goes by "Strelkov."

This week, Strelkov ordered his troops to quit using curse words that are known as part of the Russian "mat." Hey, its not like they have bigger problems to worry about -- namely whether they were in fact responsible for shooting down a passenger aircraft full of nearly 300 innocent people. 

"It demeans us spiritually and leads an army to defeat," Strelkov said in the order, according to RFE/RL

The Russian "mat" is a particularly vulgar family of curse words, which also offer a dexterous, modified applicability to a wide variety of everyday situations and sentences. The dirty words have proven so troubling that Russian President Vladimir Putin banned them from use in the Russian arts (such as film, books, theater) starting July 1.

The New Yorker explained some of the etymology of the street slang:

You won’t read it in your local family newspaper, but the law centers on the four pillars of mat: there is khuy [“c--k”], pizda [“c---”], ebat’ [“to f---”], and blyad (“whore”). Sorry about that, but the English equivalents are, if anything, rather pallid and polite. And that’s just the beginning, the base ingredients for the great lexical fantasia of mat. As Victor Erofeyev describes at delicious length in his 2003 article “Dirty Words,” there are thousands of variations and elaborations on these four words, and they go back to the earliest Russian classics.

As military leader of the self-proclaimed Donetsk People’s Republic in Eastern Ukraine, Strelkov takes his moral responsibility over his forces seriously.

"We call ourselves an Orthodox army and are proud to be serving not the golden calf, but Our Lord Jesus Christ and our people," he said, according to the Moscow Times. "Using 'mat' swearing is blasphemy against our Lord and the Mother of God, whom we serve and who cover us in battle."

The applied use of "mat" among the separatist  forces has perhaps gotten more urgent since Ukraine's military announced that it was on the verge of reclaiming the city of Donetsk from rebel control.