Hackers published nearly 5 million Gmail usernames and passwords to a Russian Bitcoin forum last Tuesday.

News of the hack was first reported by CNews, a Russian website. When contacted for comments regarding the issue, Google said that they did not believe that the publication of the Gmail accounts was due to a security breach on their end.

Google reiterated that the security of their users' information is their top priority and they have found no evidence that their systems had been breached. The spokesperson added that once they were aware that accounts may have been compromised, they immediately took the necessary steps to help those affected make their accounts secure again. 

The forum user who posted the file, tvskit, claimed that about 60 percent of the passwords were valid. The passwords have been purged by forum administrators since they were posted, leaving only the logins in the text file, Business Insider reports.

When analyzed, the posted text file showed that many of the accounts belonged to Russian, Spanish and English users. Likewise, it seemed that the posted file contained older lists that were gathered some time ago.

Analysts say that these could be hacks from sites unrelated to Google services or to Gmail specifically, and could probably be from phishing attacks and from other sites where some users chose the same usernames and passwords.

From what they could gather, it is probable that the leak significantly affects a lower number than previously estimated.

Many users may have already changed their passwords before this publication and some of those on the list could be outdated, duplicated or even suspended accounts.

A website has been created where you can check if your Gmail account is on the list. This could be risky. It is better to just change the password for your Gmail account. Google recommends that Gmail users enable their two-step verification process for added security.