TOKYO, JAPAN - Japan's financial watchdog said Friday that it had ordered Citibank Japan to suspend part of its operations for a month because of insufficient measures against money laundering.

The Financial Services Agency (FSA) instructed the bank to halt all sales activities at its retail banking division, including advertising, from July 15 through August 14, unless requested by clients.

It ordered the Japanese banking unit of the US financial giant to enhance its procedures for monitoring suspicious transactions including money laundering, and told it to submit a business improvement plan.

Citibank Japan apologised to its clients for the suspension, saying in a statement: "We are determined to take necessary measures on the issues."

It was the second administrative penalty against Citibank over its money laundering measures since 2004, when the FSA suspended some of its operations, leading to its withdrawal from private banking businesses for high-end clients in Japan.