Finally: ISIS underground military base found

A warren of terror tunnels excavated by ISIS terror thugs has been discovered by Iraqi forces.

The extensive network was unveiled after the jihadis fled the outskirts of Fallujah.

One of the longest tunnels surrounded a brick factory, Hashid Shaabi fighters said.

Islamic State used the tunnels to approach, appear and escape from the front-line to reduce their casualties.

The tunnels run under streets and between houses, where the terror thugs take cover to fight their advancing enemy.

Iraqi troops have pushed towards Fallujah from the south, aiming to completely surround the Islamic State-held city, Iraq's elite counter-terrorism forces said.

"Our troops are now in the process of surrounding the city from all (sides)," said Lieutenant General Abdul-Wahab al-Saadi, the head of the counter-terrorism forces' Fallujah operation.

"By doing so, we will besiege the city of Fallujah in full. And then we will start storming the city from several directions with new forces."

Booby-trapped explosives and large numbers of civilians unable to escape are expected to complicate operations moving forward, Lt al-Saadi said.