LOS ANGELES (CBS) — Google has issued a warning to its millions of users Thursday that a large number of accounts may have been hacked.

Users whose accounts were compromised will see warnings at the top of their browsers.

The warning says:

“We believe state-sponsored attackers may be attempting to compromise your account or your computer.”

The alerts actually started months ago, but Google has finally gone public with them this week.

(credit: Google Online Security Blog)

In a recent blog post, Google said it believes foreign governments are behind the attacks, but has not specified which countries.

Internet security experts say it’s a wake up call to be more cautious.

Users can protect themselves by creating a strong password with a mix of symbols, numbers, and capital and lower-case letters. Google users can also beef up their login by using two-step verification.