Investigators in Belarus have detained the head of Russia's largest potash producer Uralkali on suspicion of abusing his authority.
Criminal proceedings have been launched against the firm's CEO Vladislav Baumgertner and several top managers in the Belarus Potash Company (BPC).
On 30 July Uralkali pulled out of a joint trading venture with BPC.
Correspondents say that Uralkali's move could lower the global price of potash - a key ingredient in fertiliser.
A spokesman for Uralkali, quoted by Russia's RIA Novosti news agency, said Mr Baumgertner had gone to the Belarusian capital Minsk at the invitation of the Belarus government.
He met Belarus Prime Minister Mikhail Myasnikovich on Monday and was then detained as he was preparing to fly out of Minsk, company spokesman Alexander Babinsky said. Uralkali called his detention "a crude provocation".
Reuters news agency says potash is a key foreign-currency earner for Belarus.
The ex-Soviet republic's authoritarian President, Alexander Lukashenko, has largely kept in place Soviet-era economic structures, minimising price competition.