The authorities in Belarus have arrested Vladislav Baumgertner, the head of Russia’s largest potash producer Uralkali.
Invited to Minsk for a meeting with the prime minister, he was then held and charged with abusing his position and official powers, an offence that carries a prison term of up to 10 years.
This comes just weeks after Baumgertner’s firm pulled out of a partnership known as the Belarus Potash Company.
That joint venture controlled more than 40 percent of the world’s exports of potash, which is one of the most-important ingredients in agricultural fertilisers.
The joint sales pact – some called it a cartel – kept a limit on production which pushed up prices. They are now forecast to fall as much as 25 percent in the second half of 2013.
Uralkali’s shares slipped 3.36 percent in Moscow, bringing its losses to about 27 percent since the Belarus Potash Company was dissolved.
Belarus is a close ally of Russia, but the surprise collapse of the potash partnership has strained relations between the two countries.
Russian Deputy Prime Minister Igor Shuvalov was critical of the arrest and called it “rather strange and inappropriate”.
Potash is a valuable source of foreign currency for Belarus which has retained the Soviet economic model, with largely state control.