BANGKOK — A Bitcoin exchange in Thailand says it has suspended trading after officials declared the virtual currency illegal in a setback for efforts to bring it into the financial mainstream.

The company overseeing bitcoins in Thailand said on its website that the central bank informed it on Monday that it's illegal to trade bitcoins, move them in or out of the country, or use them to buy or sell goods or services.

Despite wild swings in value, the virtual currency has been inching toward broader acceptance. Atlanta-based BitPay handles bitcoin transactions for more than 4,500 companies, taking payments in bitcoins and forwarding the cash equivalent to the vendor involved.

The statement said Bitcoin Co. Ltd. had applied to the Bank of Thailand for a money exchange license as part of efforts in the past several months to ensure it was operating lawfully in the country.

The central bank had no immediate comment.

Bitcoins are created, distributed, and authenticated independently of any bank or government. The currency's cryptography makes it almost immune from counterfeiting, and its relative anonymity holds out the promise of being able to spend money across the Internet without scrutiny.

Vitalik Buterin, a writer for Bitcoin Magazine, said Bitcoin's fate in Thailand may give the electronic currency more credibility in some circles. But he was concerned it didn't bode well for Bitcoin in China.

"Thailand is not exactly a bastion of liberty," he said in an email. "This may influence it (China) to take a harsher stance on Bitcoin as well."

Calls to Bitcoin Co. were unanswered. Domain registry information shows that its website was created in June.