The Islamic State launched a counter-offensive on Tuesday, December 4 evening in the southeastern countryside of Deir ez-Zor after losing a significant amount of territory in the northern part of Hajin, Al-Masdar News reports.

According to reports from the Deir ez-Zor front, IS managed to retake several points inside of Hajin that they lost to the Syrian Democratic Forces (SDF) over the last 24 hours.

However, the extent of their advance is still unknown at this time due to the heavy bombardment of Hajin by the U.S.-led Coalition.

The town of Hajin is believed to be IS' de-facto capital in Syria and Iraq after they lost the cities of Raqqa, Mosul (northwest Iraq), Albukamal, and Mayadeen.

For IS, conceding Hajin to the Syrian Democratic Forces would be a devastating blow to their self-proclaimed ‘caliphate’, as its the largest town under their control in the Middle East.