The city of Tabqah and the surrounding area believe fallen to US-backed forces. The Islamic State had controlled the city,the Tabqah dam, and a military airbase in the area since 2013-2014. The battle for Tabqah, or which began with a surprise attack on Mar. 22,is a key part of the strategy to capture the self-declared caliphate's capital of Raqqa.
Source: longwarjournal.org