Twitter went down twice this afternoon, and it went down hard.
The microblogging site first crashed around 12:30 p.m. Eastern time on Thursday. The outage affected all platforms, taking down third-party apps, along with the Twitter apps on the Android and iOS platforms.
The site came back up around 1:15 p.m.
"Users may be experiencing issues accessing Twitter. Our engineers are currently working to resolve the issue," the company said in its Web site. "The issue is on-going and engineers are working to resolve it."
Later the company tweeted an explanation for the site failure.
"Today's outage is due to a cascaded bug in one of our infrastructure components. We'll provide updated information soon," the company tweeted.
Also Thursday, a hacker group claimed responsibility for Thursday's outages, but Twitter denied the claim.
A little after 3 p.m. ET, Computerworld received an email from someone claiming to be a member of UGNazi, also known as the Underground Nazi Hacktivist Group, that claimed it took down Twitter with a distributed denial of service (DDoS) attack.
"Twitter supports the CISPA bill and we wanted to show what we really are capable of," the group said in a separate email.
The CISPA, or the Cyber Intelligence Sharing and Protection Act, is a controversial cybersecurity bill that, if enacted, would increase the information that is shared between technology companies and the government.
The group also contacted other news organizations.
Meanwhile, users are quick to take to Twitter to vent their frustrations when an outage hits another online site, such as Facebook. But with the Twitter crash today, users had to wait for the site to come back online to tweet their complaints.
"'Hey, guys, did you hear Twitter was down?' Sent via cave painting," tweeted a user identified as jeeveswilliams. And someone named EliGP added, "The worst part about Twitter being down is that you can't tweet about Twitter being down."
Some users had a bit of fun at Twitter's expense.
"You learn a lot when #Twitter is down. For example, my wife left me four years ago," tweeted BorowitzReport. And HalaGorani tweeted, "Turns out I read a book while Twitter was down."
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin and on Google+, or subscribe to Sharon's RSS feed . Her email address is email@example.com.