BEIJING, Jul 13 (AP) -- China has arrested hundreds of people and seized over 2 billion dollars in currency since it stepped up efforts to crack down on illegal currency transactions in April last year, state media reported Wednesday.

From April to December last year, 274 suspects were arrested, the official Xinhua News Agency reported.

In the same period, authorities smashed 155 illegal financial operations and seized 12.5 billion yuan (US$1.5 billion; €1.2 billion) in currency, Xinhua said, quoting a report from the central bank.

Over the whole year, law enforcement investigated an additional 50 money-laundering deals involving a total of 570 million in yuan (US$68.8 million; €56.3 million) and 447 million in US dollars (€365 million), Xinhua said, without elaborating.

Money laundering is a growing problem in China, often linked with drug-trafficking. The government has recently ordered banks to begin regular reporting of large foreign currency dealings as part of a crackdown.

In April 2004, China established a separate center responsible for collecting, analyzing and supplying information on money-laundering activities in the country.

By the end of 2004, the center had received a total of 10,740 reports on illegal money deals, Xinhua said.

The bank report said that Hong Kong, the United States, Japan and Taiwan are the main sources of large-scale illegal money transfers, the agency said.