A pioneering internet messaging service that once boasted 100 million accounts has shut down, a message on the Russian-owned ICQ website said Wednesday.

ICQ -- styled to sound like "I seek you" -- was developed by a group of Israeli programmers in 1996 as a way for users to text chat in real-time, a novelty in the mid-1990s.

Early internet giant AOL snapped it up in 1998 and it grew into a major going concern, with the US firm claiming more than 100 million accounts in the early 2000s.

By the time ICQ was sold in 2010 to the Russian company that has since become VKontakte -- often dubbed Russia's Facebook -- it was past its peak.

However, the service briefly hit the news in 2018 when Russia banned Telegram and the government told journalists it would shift its communications to ICQ.

A message on ICQ's website on Wednesday confirmed the service had been discontinued and urged users to sign up to VKontakte's other messaging service.