A hacker claiming to be associated with Anonymous gleefully tweeted that the group had taken down MasterCard’s site with a denial of service attack Tuesday.

As of time of writing, the Web site had been restored.

This marked the second attack the hacktivist collective has waged on MasterCard for refusing to do business with WikiLeaks, Julian Assange’s whistleblower Web site. The first, dubbed Operation Payback, took the company’s site down for several hours.

A tweet from Wikileaks following the reports that MasterCard’s site had been taken out showed that several companies still refuse to associate with the group.

The unlawful banking blockade against WikiLeaks in 6th month: The culprits: VISA, MasterCard, PayPal, Bank of America, Western Union.Tue Jun 28 11:04:16 via webWikiLeaks

Anonymous is clearly continuing its hacking campaigns, which haven’t slowed down one bit since the LulzSec hacker group announced it was disbanding over the weekend after 50 days of hacks.

Related stories:

Blog Post: Julian Assange auctions himself on eBay

LulzSec done after 50 days of hacks

Blog Post: LulzSec disbands: A timeline of 50 days of hacks

These six companies have fallen to attacks in recent months

GALLERY: Click the image above to view the gallery.