A network of websites that kept track of the deleted tweets of politicians in Canada and 30 other countries has shut down after Twitter cut off access to its data.

The Politwoops sites automatically monitored politicians' Twitter accounts in more than 30 countries, and showed the tweets' content, when they were deleted and how long they were up.

The Open State Foundation said Twitter suspended its access to Twitter's application program interface (API) on Friday night, effectively shutting down the entire service.

Twitter had previously blocked API access for the U.S. version of Politwoops, which shut down May 15.

In its release, the Open State Foundation quoted a representative of Twitter explaining the decision:

"Imagine how nerve-racking — terrifying, even — tweeting would be if it was immutable and irrevocable? No one user is more deserving of that ability than another. Indeed, deleting a tweet is an expression of the user's voice."

Politwoops began at a programming event in 2010 in the Netherlands and later spread to more than 30 other countries, including Egypt and Tunisia, as well as the European Parliament.

"What elected politicians publicly say is a matter of public record," said Arjan El Fassed, director of Open State Foundation, in a statement.

"Even when tweets are deleted, it's part of parliamentary history. This is not about typos, but it is a unique insight on how messages from elected politicians can change without notice."

The group said it will continue to explore ways to maintain a service to show changes in public tweets by elected politicians.