The dollar's steep decline in interbank trading has prompted the Bank of Japan to intervene repeatedly in currency trade over recent weeks.

Despite the BOJ's intervention, however, the dollar remains under downward pressure.

Concerns over a slower-than-expected U.S. economic recovery, plus fears of fresh terrorist attacks on the U.S., are weighing on the dollar. Other factors apparently at work include renewed worries over the U.S. trade deficit and corporate accounting practices aimed at inflating earnings.