The Arab “branch” of the Anonymous hacker group on Sunday said it had stolen large numbers  of credit card information, e-mail logins, and other personal data from Israelis. The group posted several of them on their Facebook page, and Israeli officials said that they appeared to be genuine.

A security expert for an Israeli computer security company recommended that individuals change their passwords. The expert said that the hackers had apparently broken into a single server, and were unlikely to have information on any more than 300 or so accounts.