The online encyclopedia Wikipedia was vandalized on Monday by a user who was able to edit a template so that swastikas were added to 53,000 pages.

Wikipedia, which is volunteer maintained, saw Nazi flags added to pages for a host of prominent figures, including President Joe Biden, Vice President Kamala Harris and Canadian Prime Minister Justin Trudeau. Entries for many TV shows, actors and celebrities, including Madonna, Jennifer Lopez and Ben Affleck, were also targeted.

When peopled attempted to access the pages that were affected, they found no text or images. Instead there was only a swastika on a red background.

Gizmodo reported that the culprit behind the hack was able to edit a template used for 53,000 pages. He was therefore able to deface pages that are supposed to be locked from access in order to protect them from being attacked.

The problem was quickly fixed by Wikipedia administrators within five minutes, and the user’s account was blocked.

Fifteen minutes later, Wikipedia volunteers had locked down the template so the incident could not happen again.

"In the spirit of open editing and assuming good faith, this is a step rarely taken with any areas of Wikipedia unless an incident such as this warrants it," said a spokeswoman for Wikimedia, reported Cnet.

It was noted by Wikipedia that most templates are locked but some are still open to being edited by anyone. In this case, the vandal was apparently a new user who made several constructive edits at first to fool the site before staging the attack.

The Wikimedia Foundation, which oversees Wikipedia, called the attack “particularly vile,” according to Cnet.

Because it is volunteer-driven, Wikipedia has been hit with offensive edits in the past but those usually only targeted a single entry.

Wikimedia Foundation told Gizmodo that the attack was “unacceptable” and violated “a number of Wikipedia’s policies.”