Earlier Friday, an administration official said the Justice Department had been "taken to task" for not coordinating its announcement with Homeland Security and other agencies.

CNN: Out of sync on warning?

Before the announcement, the scale of the task of reflating Japan was underlined by inflation data, showing prices fell by 0.5% between March 2012 and March 2013.

BBC: Bank of Japan lifts economic forecasts

The announcement of an impending price increase will only help make that task more difficult.

BBC: A highly charged debate