A top U.K. commander said Monday that a large batch of intelligence documents belonging to the Islamic State group was recovered during operations in northern Syria, revealing terror attacks planned across the world.

Major General Rupert Jones, the most senior U.K. commander in Iraq and Syria, first made the announcement Sunday while addressing politicians and diplomats on the current fight against the militant group also known as ISIS. He said some 10,000 documents, which included hard drives, USB flash drives and other forms of data storage, were seized following the push by Western-backed Syrian rebels to drive ISIS out of the city of Manbij in August. The contents were being processed at the Kuwaiti headquarters of the Western-led operation to defeat ISIS, whose self-proclaimed caliphate has suffered territorial defeats after taking large swathes of land in Syria and Iraq.

Without revealing any specific plots, Jones confirmed Monday to reporters at the Al Assad Air Base in Iraq that the recovered documents did involve international terror operations. He stated that Manbij, along with the Syrian city of Raqqa and the de facto capital for ISIS, acted as headquarters for coordinating terror efforts abroad. 

"External operations have been getting orchestrated to a very significant degree from within the caliphate, critically from within Raqqa and from within Manbij," Jones said, according to Sky News.

"They were key external operations hubs. There is a huge amount of intelligence, documentation, electronic material that has been exploited there that points very directly against all sorts of nations around the world," he added.

He went on to say that defeating ISIS was crucial for preserving national security in the U.K., where counterterrorism police units have taken to the streets. Europe has been on high alert since being targeted by a number of ISIS-conducted and inspired terrorist attacks in the past two years. In the deadliest incident, ISIS militants killed 130 people in a series of gun and suicide bomb attacks in Paris last November.

As ISIS continues to be uprooted in Iraq and Syria, concerns among Western countries are growing that the militants will increasingly set their sights on the U.S. and Europe.