Some Google+ users are complaining that Facebook is making it harder for friends to access their posts on the competing social network, by throwing up a security warning on Google+ links. Facebook is claiming security issues, and has its partner, Norton Antivirus-maker Symantec, to back it up. But users are crying foul.

Several Google+ users who have set the service to automatically update their Facebook pages say when friends click on the links directing them back to their Google+ profiles, they get a Norton Antivirus-branded warning message reading, in part, that “the link has been identified as potentially unsafe.” Facebook signed a deal with Symantec to offer free antivirus protection in April.

We’ve asked Symantec and Google for comment and will update this post when we hear back from each company.

Update: Facebook spokesman Frederic Wolens said the company would "never" use its external blacklist system for competitive reasons.

"We integrate with many different external blacklists including Norton and when there's a block on their service we provide a warning to our users," Wolen said in an email. "I have already reached out to Norton to notify them, however, the cause for the block is a question best suited for their PR Team." 

“Both companies know that a link to Google+ is perfectly safe. There are no banner ads and no way for malicious code to be downloaded from Google+. There has never, to the best of my knowledge, been a malware event originating from a Google+ link,” Mike Elgan wrote in a Google+ post to his followers. “Even after you click "Ignore this warning," every single link is flagged in the same way, with no "learning" or option to accept all links from the site.”

Update: Elgan added another Google+ post saying Facebook had removed the warnings, but some commenters said they were still seeing a warning, only without the Symantec branding. 

Tech blogger Liron Segev went one step further, running Norton’s Safe Web Check on Google+. The check came back with no identified threats.

“The posts are harmless. There is no code embedded in them, no advertising  and no contravening of the Facebook policy. In other words, there is no reason to block posts from Google+,” Segev wrote. “The exact same post from WordPress... seems to work perfectly fine with no ‘Security Alert: This Link May Not Be Safe’ message.”