July 2 (Reuters) - Thailand"s financial watchdog filed a criminal complaint against cryptocurrency exchange Binance on Friday for operating a digital asset business without a licence, the latest in a string of crackdowns on the platform by regulators globally. Thailand"s Securities and Exchange Commission (SEC) said in a statement that Binance had been operating a digital asset business "in the category of a digital asset exchange" without a licence. In Thailand, only licensed firms are allowed to provide services related to digital asset trading, the SEC said. The Commission had warned Binance over its activities in a letter in April but received no response, it said, leading it to then file a criminal complaint with the Thai police. A Binance spokesperson declined to comment specifically on the Thai complaint, saying it takes a collaborative approach to working with regulators and takes its compliance obligations seriously. Britain"s financial watchdog last week barred the company, one of the world"s biggest exchanges, from carrying out regulated activities in the country. read more Japan"s regulator said last week Binance was operating in the country illegally, while Germany"s watchdog said in April it risked being fined for offering tokens connected to stocks. read more In May, Bloomberg reported Binance was under investigation by the U.S. Justice Department and Internal Revenue Service. read more The complaint filed in Thailand by the SEC is the start of a criminal procedure, with a police investigation possibly leading to a recommendation to a public attorney who has authority for prosecution, the Commission said. The offence carries a penalty of two to five years imprisonment, a fine of 200,000-500,000 baht ($6,200-15,500), and a further daily fine of up to 10,000 baht for every day the contravention continues, it added. Trading volumes at the exchange in June were $662 billion, up almost ten-fold from July 2020, according to data from CryptoCompare. read more ($1 = 32.1900 baht)