Alphabet Inc (GOOGL.O) said today it was investigating widespread reports about a spam campaign in which recipients received emails from known contacts that asked them to click on a link to review a Google Docs document.

If someone invites you to edit a file in Google Docs today, it would be a good idea not to open it. It could very well be spam from a phishing scheme that’s been spreading quickly this afternoon. The attack targets an emailed invitation from someone they may know, takes them to a real Google sign-in screen, then asks them to “continue to Google Docs.”

However, this grants permissions to a malicious third-party web app that’s simply been named “Google Docs,” which gives phishers access to your email and address book.

“We are investigating a phishing email that appears as Google Docs. We encourage you to not click through & report as phishing within Gmail,” the company said on its Google Docs Twitter account.