UPDATE 3-U.S. indicts Iranians for hacking dozens of banks, New York dam

WASHINGTON, March 24 (Reuters) - Seven Iranian hackers broke into computers of dozens of U.S. banks, causing millions of dollars in damages, and tried to shut down a New York dam, the U.S. government said on Thursday in an indictment that for the first time accused individuals tied to another country of trying to disrupt critical infrastructure.