After a full shutdown Monday night and sporadic access throughout Tuesday, it appears the popular online classified ads website Craigslist is back up on running.

Craigslist's 55 local Canadian sites went down Monday night, with users being redirected to a rather cryptic message from the company that said violations of the site's policies were behind the shutdown.

But by Tuesday afternoon, some users were reporting through Twitter that the sites were back up and running for them. By Tuesday evening, the site appeared to be operating as usual.

Earlier Tuesday, on the main Craigslist website system status page, it posted a brief message:

"Hello, Canada! Technical issues are currently affecting access to craigslist Canada sites for many users. All hands are working to get this sorted out asap. Sorry for the inconvenience. In the meantime, try clicking the city you'd like below."

While users were able to click-through to city pages like Toronto and view ads, clicking onto them simply takes users back to the same page explaining that there were technical issues.

Other Craigslist sites, including in the U.S., Europe and Asia, appear to be functioning normally.

Earlier on Tuesday, a cryptic message appeared on the Canadian Craigslist's sites that read: "The website formerly operating at this domain violated craigslist's Terms of Use and/or enabled or facilitated others in violating the TOU, and/or infringed craigslist's trademark(s) or other intellectual property."

"Craigslist does not permit automated posting or the employment of posting agents (software or human)," continued the notice. "Users who post non-local or irrelevant content, repeatedly post the same or similar content, or otherwise misuse craigslist's services detract from the user experience for all craigslist users."

The notice provides no explanation of the incident or incidents that might have prompted the shutdown.

A number of media outlets have attempted to contact the company seeking more information on what has caused the sites to go down, but it appears the company has not replied to any requests for comment.

Some users on Twitter are suggested the sites have not been shut down but were instead the victim of a "denial-of-service" attack.