(Adds court decision on Adams' detention)
PRAGUE, Aug 21 (Reuters) - Czech police have arrested the American boss of truckmaker Tatra on charges of bribery, a company spokesman said on Tuesday, the latest step in an anti-corruption drive which has seen several ministers and senior government officials facing charges.
However, a court ruled later on Tuesday that Ronald Adams, who has run privately-owned Tatra since 2006 as chairman, would not be taken into custody as requested by the police who have charged him with offering a bribe to win army contracts, Tatra spokesman Vladimir Bystrov said.
"The court found there were no reasons why Mr. Adams should remain in custody," Alexandr Cesar, Adams' attorney, told Reuters. No bail was required.
The company had said in a statement the charges, which it said were brought by witnesses themselves charged with bribery, were groundless.
The case, which Czech media say involves former Defence Minister Martin Bartak as a witness, is the second major corruption scandal to erupt around army contracts in the European Union member state this year.
Another former defence minister, Vlasta Parkanova, has been charged with improperly handling state property in connection with the purchase of military planes, a contract critics said was too expensive.
Parkanova has also denied the charges.
A police spokeswoman declined to confirm Adams had been arrested, but said: "We have charged a 62-year-old man with bribery in connection to contracts with the Czech Army."
The U.S. embassy in Prague said only that it was monitoring the case closely.
The army contracts scandals are just the latest to shake the political and corporate establishment in the country of 10.5 million, damaging parties' standing with Czech voters, though few cases have led to convictions.
A Transparency International study last month said prosecution in the Czech Republic was "weak" and "vulnerable to direct political influence".
In June, the Czech parliament lifted immunity from prosecution for a top opposition official, David Rath, who was arrested this year while leaving a friend's house with 7 million crowns stuffed in a wine box.
Newspaper Mlada Fronta Dnes reported on Tuesday that the main witness in the Tatra case is former defence chief Bartak, who resigned as deputy finance minister when the charges surfaced but denies any wrongdoing.
He has been accused by Tatra officials, including former U.S. ambassador William Cabaniss, of requesting a bribe in 2008.
Adams purchased a 92 percent stake in Tatra with three partners in 2006. He served for a time as president of the American Chamber of Commerce in Prague.
The company, which dates back to 1850, posted revenue of 4.3 billion crowns ($213.45 million) in 2010, according to its website.
Czech prosecutors are taking on more cases of official corruption, the top complaint in voter surveys.
In May, a state attorney ordered the reopening of an investigation into contracts with electricity company CEZ and a supplier.
Former CEZ Chief Executive Martin Roman has been accused by a Czech newspaper of having a conflict of interest due to alleged ownership links to the supplier. Roman has denied the accusation. ($1 = 20.1448 Czech crowns) (Reporting by Robert Mueller and Jana Mlcochova; Writing by Jason Hovet; Editing by Jan Lopatka and Stephen Nisbet)