Russia has detained the US head of a major investment firm on suspicion of fraud and he will appear in a Moscow court on Friday, the court said.
Michael Calvey, the founder of multi-billion-dollar investment fund Baring Vostok, was named in a court document as having been arrested and facing potential fraud charges.
Several other people from the fund and other businesses were being held in connection with the suspected fraud, a court spokesperson told Russian news agencies.
Among them was French citizen Phillipe Delpal, who oversees investments in the financial industry for Baring Vostok.
The firm confirmed in a statement that four of its employees had been detained, without providing their names.
It said the charges related to a commercial dispute over the Vostochny Bank, but provided no further details.
"The actions of law enforcement are not directly related to the activities of Baring Vostok and other portfolio companies," the statement said.
Delpal appeared in Moscow's Basmanny Court on Friday for a detention hearing, an AFP journalist at the court said.
"I strongly object to the request for a detention," Mr Delpal told the court in English. "I have no connection with the alleged crime."
Mr Delpal said he had lived in Moscow for the last 15 years, and has a wife and two daughters in the city.
Russian Deputy Prime Minister Anton Siluanov told news agencies that the foreign investors, if found guilty, should expect to feel the full force of the law.
"If this is a fraud, what can I say: do not violate the law. If the facts are confirmed, no one can spare the perpetrators," he said on the sidelines of an investment forum in the Black Sea resort of Sochi.
"Be it a foreigner or a Russian, there is no difference here."
The Baring Vostok fund specialises in private equity investments in Russia and the former Soviet Union.
Since 1994, the fund has invested more than $2.8 billion in companies in the region, according to its website.
It employs more than 40 people in Moscow and has invested in major Russian companies including internet giant Yandex, media company CTC and telecommunications firm Golden Telecom.
A source familiar with the investment firm told AFP that the case could be an attempt by a local competitor to damage it.
The source said it would be a "huge surprise" if the charges were founded.
"They're among the most professional investors in the Russian markets, there's never been any issues," the source said.
"It's extremely negative for investment, very damaging."
As well as founding the firm, Mr Calvey is a senior partner.
Before moving to Moscow he worked in London and New York on oil and gas investments for the European Bank for Reconstruction and Development, according to a biography on the fund's site.
Mr Calvey is also on the board of directors of the Atlantic Council think tank.
Mr Delpal joined Baring Vostok in 2012 after founding Cetelem Russia, part of the BNP Paribas Group, according to his biography.
The pair are not the first foreign investors to fall foul of the law in Russia.
American-born Bill Browder, once the biggest foreign investor in Russia, faced a string of criminal charges in 2008 after his lawyer Sergei Magnitsky revealed a massive fraud by state officials.
Both were charged with tax fraud, but Magnitsky died in pre-trial detention of untreated health issues.
His case later inspired the US Magnitsky Act intended to blacklist Russian officials implicated in human rights abuses.
Browder meanwhile was sentenced in absentia to nine years in jail.