(CNET) It was a confusing day in the Twittersphere as users were met with a spotty site service outage this morning. The service went down and up multiple times in a two-hour period beginning around 9 a.m. PT.
Twitter said the outage's cause wasn't an attack, but a failure within Twitter's system.
"Today's outage is due to a cascaded bug in one of our infrastructure components," the company's communications folks tweeted at 12:17 p.m. "We'll provide updated information soon."
Now, a hacker group, UGNazi, said it's actively attacking the site, CBS Atlanta reported.
Hacker Hannah Sweet, known as "Cosmo" and @CosmoTheGod on Twitter, is claiming that UGNazi took Twitter down for 40 minutes worldwide with a "distributed denial of service" attack and the hackers are continuing the attack.
Sweet said that the group attacked Twitter because of the site's support of Cyber Intelligence Sharing and Protection Act (CISPA), a bill that allows the federal government and private businesses to share information about possible cyber threats.
After Twitter said its service was back up mid-morning after more than an hour of service interruption, the site went down again.
"Update: The issue is on-going and engineers are working to resolve it," the status read at 10:57 a.m. The site's service continued to yo-yo into the afternoon.
Twitter appeared to be completely down starting 9 a.m. PT, according to monitoring site Pingdom. According to the stats on Pingdom, this looks to be Twitter's worst crash in months.
This article first appeared at CNET.