A campaign believed to be tied to the Iranian government tried to hack into the emails of U.S. presidential candidates, government officials, and journalists thousands of times during the past two months, The Washington Post reports. Microsoft said the hackers made more than 2,700 attempts to identify email addresses that belonged to its customers over a 30-day period in August and September. The attack reportedly involved hackers trying to figure out how to reset account passwords. The attackers also reportedly had gathered phone numbers associated with some account holders to authenticate the password resets.

Of the attempts, 241 were successfully attacked and four were compromised. Microsoft said the four accounts that were compromised did not belong to presidential campaigns or government officials, but declined to name the account holders. The tech giant also said it worked with those four customers to properly secure their accounts.