The Waukegan Police Department is urging residents to use caution when visiting ATMs after dark.
Over the past few days, the police have responded to calls at ATMs at various banks in the city. There were two robberies and two attempted robberies.
In all of the incidents, the victims were attempting to use ATMs after dark and were approached by at least two thieves after making a transaction. Police said the victims were ordered to surrender their money or to withdraw more money from the ATM.
No one was injured, police said.
The thieves were all described as young men in their late teens wearing ski masks and displaying black handguns.
"The Waukegan Police Department stresses that people should avoid using ATMs after dark," said Police Chief Daniel Greathouse. "If you find that you must utilize an ATM after dark, please use one that is located indoors at a business such as a grocery or department store."
Greathouse said the police department is working on several leads.