Belarus detained the head of Russia’s Uralkali, the world’s top potash producer, after he met the country’s Prime Minister yesterday, drawing a fierce rebuke from Moscow in an escalating dispute over the collapse of a cartel.

Vladislav Baumgertner was detained on suspicion of abusing his position and official powers over Uralkali’s decision to quit the Belarusian Potash Co (BPC) joint trading venture, according to investigators in Belarus.

If charged and found guilty, Baumgertner could face up to 10 years in prison.

It is the first time a top manager of a Russian firm has been detained in Belarus, run since 1994 by President Alexander Lukashenko, who styles himself as “Europe’s last dictator”.

Belarus is Moscow’s staunchest ally among former Soviet republics but its economy is stagnating after a financial crisis in 2011.

The intensification in tensions between Minsk and Moscow comes as the centrally planned Belarussian economy faces a widening of external deficits that, economists say, risks a repeat of a currency collapse suffered in 2011.

The clash is symptomatic of dysfunctional trading relations that blight the former Soviet space – even though Russia, Belarus and Kazakhstan have formed a joint customs union and are the anchor economies in a broader regional economic partnership.