The remnants of the Islamic State have returned to the group’s insurgent roots since the destruction of its land caliphate earlier this year, but it may be regrouping to make another land grab, the Pentagon says.

The terrorist group has been operating in a “clandestine” fashion since losing the last of its territory in Iraq and Syria, said Chris Maier, director of the Pentagon’s Defeat-ISIS Task Force, in a Wednesday press briefing.