Two weeks ago, clever thieves in Belgium made off with nearly 4,000 iPhone 3GS units from a warehouse belonging to carrier Mobistar. Now the stolen phones are starting to appear in Russia, of all places.

The black market iPhones are valued at $3 million US and are currently being offered in Russia in batches of 100 at bargain prices, according to Russian website iPhones.ru. And needless to say, the transaction is cash only.

“Today, several vendors with a forum reported that they call the unknown people and offer at knockdown prices to buy officially unlocked ‘Europeans’,” a Google translation of the report reads. (“Europeans” refers to the stolen iPhones.) “The minimum party is from 100 units in one-time payment without there installments or implementations. The owner of a shop at Gorbushka, speaking on condition of anonymity, confirmed that the windows of the market has already started to appear Belgian phones.”

Russia’s carrier MTS got the exclusive on the iPhone 3G last year, but sales were lackluster compared to other countries, especially considering the carrier’s 84 million subscribers. The biggest problem stems from the official iPhone’s hefty price, especially when compared to the healthy trade in unlocked iPhones from other countries — even President Dmitry Medvedev is rumored to own one!

International police agency Interpol is already on the case of the stolen iPhones, with serial numbers on hand so they can confiscate them if found. But it seems that Russian vendors are already wary of the units anyway, especially since Interpol has the ability to have local wireless carriers block the units’ IMEI (International Mobile Equipment Identifier) numbers, rendering the phones useless.

iPhones.ru is also advising Russian customers with new iPhones to check their devices to make sure they’re not one of the stolen ones.