Android users of the popular instant messaging app WhatsApp have noticed that it is blocking links to rival chat service Telegram. It was reported on Reddit that although the URLs still appeared as messages, they did not register as hyperlinks and users were blocked from copying and pasting them into another app.

The issue only began appearing in the updated 2.12.367 version of the app that was rolled out today. Telegram links are still working on the iOS version of WhatsApp, but that may change as the update reaches more devices. The Verge reported that the block also includes, a URL owned by a newspaper in Worcester, Massachusetts, that has no relation to the app.

It's still not known whether the link is an intentional block of Telegram or a new bug within WhatsApp. Facebook, the messaging service's owner, has used link-blocks on several previous occasions within its social network; it was recently criticized for blocking any mention of, a site that pays users a percentage of its ad revenue for each post.

If Whatsapp is intentionally censoring Telegram links, it will be the first instance of it blocking a major site. A spokesperson for the privacy-focused messaging service said: "Typically after a media backlash, FB steps back and blames their intelligent filtering for the problem. We expect the same to happen this time as well."

Telegram recently came under the worldwide media spotlight, after revelations that the app was being used as a promotional and recruitment tool by ISIS. The company later announced that it is taking measures to block access to dozens of public channels used by the terrorist group.