Updated

A Syrian rebel group has released a video showing what appears to be a massive underground command center used by the country’s brutal regime to direct its war operations, VOA News reports.

The hidden multi-story underground city was used “as a second building to rely on in case something happens to the main one inside the capital,” Syrian analyst Oula A. Alrifai told the news outlet.

It was also equipped with advanced security and intelligence technology, the Army of Islam rebel group claims.

“In the beginning we thought it was just a hideout,” rebel Commander Abu Sami said, according to the media outlet. “Our experts believe the regime had it for emergency situations to direct the war in the entire country.”

The rebel group, Army of Islam, reportedly seized the center in February after an intense September offensive against Syrian President Bashar al-Assad’s troops in the town of Harasta, northeast of Damascus.

The group claims it was also able to locate secret military documents that belonged to the Syrian army, as well as an area designed to plan chemical weapons attacks.

The seizure marks a major loss for the Syrian government in Damascus, where it has boasted control despite a slew of rebel attacks since the dawn of the civil war in 2011.

But the rebels have struggled to gain ground in recent months as Russian airstrikes and Iranian-led ground troops rushed to help the Syrian regime fight back.