BEIJING, Dec. 19 (Xinhua) -- Chinese police have uncovered seven large underground banks this year, involving money laundering of more than 14 billion yuan (1.75 billion U.S. dollars).

    Forty-four people have been arrested in Guangdong, Shanghai, Beijing, Inner Mongolia, Liaoning and Heilongjiang, and 58 million yuan has been seized or frozen, said Han Hao, deputy director of the economic crime investigation department of the Ministry of Public Security, on Tuesday.

    Authorities in the business hub of Shanghai have broken a five billion yuan (633 million U.S. dollars) money laundering case, according to Han.

    A suspect from Singapore and three other people have been arrested. The Singaporean is accused of operating an underground bank in Shanghai, making remittances, providing foreign exchange and other banking services between Singapore and China. The operation was active in 25 large and medium sized cities in China, Han said.

    "Money laundering is mainly conducted through the financial system, underground banks, online banks, cash smuggling, investment, international trade and security and the futures market," Han said.

    "The fight against money laundering will help control other crimes closely connected with it, such as organized crime, drug trafficking, terrorist activities, smuggling, corruption and financial fraud."

    But he did not give the exact figure on how much money was laundered in China every year.

    Cai Yilian, deputy director of the anti-money laundering bureau of People's Bank of China (PBOC), or central bank, said, "We haven't had all the statistics, since anti-money laundering operations started very late in China."