WhatsApp has started blocking links to one of its biggest competitors

Facebook-owned messaging app WhatsApp is blocking outbound links to Telegram, the secure messaging service that has grown in popularity since the Edward Snowden leaks.

Reddit user Shlagger noticed the problem, which affects anyone trying to send a link a Telegram domain - such as telegram.me or telegram.org - resulting in a dead link that cannot be copied and pasted out of the app.

It's unclear why WhatsApp has taken this step, which effectively blocks anyone who wants to use the service to facilitate a conversation on Telegram.

The feud has been a long time coming, however. Telegram founder Pavel Durov said on-stage that he was "not ... a big fan of WhatsApp about three years ago, and I'm not sure I am now."

The Verge confirmed with Telegram that change was a result of a silent update which downloaded to user's phones yesterday morning. The update also blocked Telegram.com, an unrelated domain owned by a newspaper in Worcester, Massachusetts.

Facebook has a history of blocking links, including those to torrenting site Pirate Bay and the social network Tsu.co. These links are blocked within Facebook's main app, not WhatsApp, however.

Business Insider has reached out to Facebook to clarify why Telegram is blocked. We will update the post when we hear back.