NEW YORK Twitter is adding an extra security measure to users' accounts in an effort to prevent unauthorized logins.
Twitter said in a blog post Wednesday that users will be able to enroll in a login verification program. For those who sign up, Twitter will send a six-digit code using a text message each time they sign in to Twitter.com. Besides their username and password, users will have to enter the code to log in as well.
Microsoft Corp., Google Inc. and Facebook Inc. already allow two-step verification as an option. Twitter has been criticized for not having this option, especially followingof Twitter accounts belonging to major news organizations and other companies.
In April, the Associated Press' twitter account was hacked, leading briefly to a dive in the stock market.
Previously, the Twitter accounts of the International Federation of Association Football (FIFA) and BBC Weather were both hacked. CBS News' "60 Minutes" and "48 Hours" Twitter accounts also were compromised.
A hacking group going by the name of the Syrian Electric Army has claimed responsibility for many of the breaches. Typically, the hackers spread political messages and misinformation.
"People are gunning for the media because that's a great way to spread a message," Sophos senior security advisor Chester Wisniewski told CBSNews.com.