The top U.S. general in Iraq has warned of the potential collapse of Mosul Dam in the country's north, saying that such an event could prove "catastrophic," despite preparations already in place.

U.S. Army Lt. Gen. Sean MacFarland said Thursday the U.S.-led coalition is still determining the likelihood the hydroelectric dam will collapse. It has suffered from poor maintenance and erosion.

He says that the U.S.-led coalition and Iraqi forces have plans in place but warns that "when it goes, it's going to go fast and that's bad."

Mosul Dam, one of the largest in Iraq, supplies electricity and water to much of the country. The Islamic State group seized the dam in 2014, but Iraqi forces and Kurdish fighters took back the structure with coalition air support within weeks.