The United States, concerned that Iran is behind a string of cyber-attacks against U.S. banking sites, has considered delivering a formal warning through diplomatic channels, but has not pursued the idea out of fears that doing so could escalate hostilities, according to American officials.
At the same time, the officials said, the disruptive activity against the websites has not yet reached a level of harm that justifies a retaliatory strike.
The internal discussion reflects the complex nature of deciding when and how the United States should respond to hostile cyber-actions from other countries. It also reflects the pressure the administration is under from banking industry officials, who want to know what amount of pain or damage will justify a government response.