A senior American Treasury Department official says Macau has pledged to combat money laundering, after the United States charged a bank in the former Portuguese colony was working on behalf of North Korea.

Last month, the U.S. Treasury Department put Macau's Banco Delta Asia on an international money laundering blacklist.  Officials in Washington said the bank has been providing irregular financial services for North Korea for the past 20 years.

Bank executives allegedly accepted large cash deposits including counterfeit U.S. dollars from North Korean officials, and put the money into circulation.

Banco Delta Asia denied the allegations but customers, fearing a collapse soon, withdrew 10 percent of the bank's capital.  The government of Macau, the former Portuguese colony that was returned to Chinese control in 1999, is now administering the bank, to prevent the scandal from spreading through the city's financial sector.

U.S. Treasury Undersecretary Stuart Levey, who is charged with uncovering financial crimes and other acts related to terrorism, says authorities in Macau are taking the matter seriously. 

Speaking in Hong Kong Wednesday just after he returned from Macau, Mr. Levey declined to say what would persuade the United States to lift its sanction against Banco Delta Asia, but he said Macau's move to enact an anti-money laundering law is an encouraging development.

"Putting that law into place is absolutely essential considering the nature of their financial system and the amount of commerce that occurs in Macau," said Mr. Levey.

Mr. Levey is on a weeklong trip through Asia, surveying the region's moves to curb money laundering and terrorists' financial networks.

At his next stop, Beijing, Mr. Levey says he will relay the United States' concern that North Korea uses illicit financial procedures to support its efforts to assemble weapons of mass destruction.  The Treasury Department official says finding and disrupting the financial networks that support weapons proliferation is a top priority.

"There is a financial network that underlies proliferation, just as there is for terrorism.  What I am hoping for is, what this trip will catalyze is that this is something the world will look at in the same way," he added.

Last week, the U.S. Treasury Department accused eight North Korean companies of supporting the proliferation of weapons of mass destruction, and ordered their assets frozen in the United States.