TEHRAN, Young Journalists Club (YJC) - Daesh, which uses messaging application Telegram to broadcast daily updates on military operations and claims of attacks, published nothing between 0900 GMT on Wednesday and 1001 GMT on Thursday.
Charlie Winter, senior research fellow at the International Centre for the Study of Radicalisation and Political Violence, called the silence "unprecedented."
"The deceleration in the production of IS media has been particularly profound over the last couple of weeks," said Winter.
"But there were no 24-hour periods when it was completely silent," he told AFP.
Daesh's Telegram channels usually post more than a dozen messages each day, ranging from multilingual radio broadcasts to pictures of civilian life in the group's self-styled "caliphate."
On Wednesday, however, the group posted in a brief 30-minute window, skipping its usual "daily broadcast" entirely.
It then went dark until Thursday, breaking its silence with a four-minute radio segment on operations in eastern Syria and Iraq, only in Arabic.