The agency says the state's failure to pay part of the nearly $400 million it owes the RTA is the reason.
The RTA says it has exhausted its ability to borrow money.
In a letter to Governor Pat Quinn, the agency said it will begin to divert money from transit operations in order to pay for borrowing within the next 30 days.
The RTA says service cuts could dramatically affect over 2 million daily riders and 15,000 RTA employees.
