Google's (GOOG) Chrome browser blocked users from multiple websites -- including its own YouTube video site -- Saturday due to suspected malware, mirroring a situation earlier in the week when ads served across the Web barred Chrome users.

Complaints on Twitter began appearing around 1 p.m. Pacific time Saturday, with users reporting varied sites -- including MercuryNews.com, YouTube, NBC News, The Verge and several smaller destinations -- returning a red Chrome malware warning that blamed a site called us.bernerverein.ch, "a known malware distributor."

On Google's diagnostics page for the site, the search giant says "Google has not visited this site within the past 90 days. Suspicious activity was detected over 90 days ago, but no data is available for the past 90 days." The page also says that the website did not appear to infect any users in the past 90 days, nor has any malware been detected on the site in the past 90 days.

The site appearing at www.bernerverein.ch appears to belong to the Bernese Club for the University of St. Galan in Switzerland -- Bernese refers to natives of the Swiss area of Bern. "Berner verein" is German for "Bernese club," and German is the official language of Bern, a canon, or state, in Switzerland that also has a capitol city of the same name.

Twitter user @ThumperPictures, which advertises its YouTube site on its profile, reported in a tweet just before 1 p.m. Saturday that Chrome had blocked YouTube; the user confirmed when asked that the publisher in his malware message was the same. Dozens of other Twitter users also reported being blocked, several citing YouTube as the site they were attempting to access.

"ok so chrome wont let me go to youtube cuz malware was put on the page. which means i cant look up this movie for my paper. great....," @_llcoolkay tweeted at 1:16 p.m.

One of the first websites to be informed by users of the issue on Twitter, "Game of Thrones"-related site WinterIsComing.net, believes that the issue stemmed from an ad, site administrator Phil Bicking said Saturday. In a discussion on the blog's core Twitter account, @WiCnet, Bicking said that the widespread nature of the warnings on the site would indicate the issue had to be an advertisement; the site does use Google's advertising services, but also relies on other advertising providers, he said.

The errors are similar to the experience of many Chrome users earlier in the week, when error warnings spread wide Monday morning after a Silicon Valley advertising-services company's website was hacked with malware.

In the earlier case, Santa Clara-based Netseer's corporate website was infected, which caused Chrome to block it; however, the company's ad-serving infrastructure and corporate website used the same domain, so any ad served by Netseer caused Chrome to block the page.

Google did not immediately respond to an email request for comment Saturday, outside normal business hours, but said in response to Monday's incident that it does not comment on individual malware cases.

Contact Jeremy C. Owens at 408-920-5876; follow him at Twitter.com/mercbizbreak.