Despite the destruction of the Islamic State’s physical caliphate in March, thousands of its fighters have simply gone underground and remain a significant threat, carrying out deadly attacks, a senior coalition military officer said Tuesday.

“It has been reorganizing itself into a network of cells and intent on striking key leaders, village elders, and military personnel to undermine the security and stability in Iraq and Syria,” British Maj. Gen. Chris Ghika, a senior spokesman for Operation Inherent Resolve, said from Baghdad in a briefing for Pentagon reporters.