DES MOINES, Iowa (AP) -- Iowa's largest energy company say thieves have attempted to steal copper at several substations in the Des Moines area in recent weeks.

MidAmerican Energy Co. on Wednesday asked customers to report any suspicious activity they see around power poles or other MidAmerican property, including individuals damaging poles, entering substations or carrying coiled wire when there are no MidAmerican vehicles in the area.

MidAmerican warned that thieves are in danger of suffering from serious electric contact and can put workers at risk and disrupt customer service. The utility noted that anyone caught stealing copper could face felony charges under an Iowa utility trespassing law.

Des Moines-based MidAmerican provides electric and natural gas service to customers in Iowa, Illinois, Nebraska and South Dakota.