Same here got a call, picked it up but no one said anything, just silent.

I have received a call today 9/13/16 from 660-787-0452. They left me a auto voicemail stating IRS was filling a lawsuit against me and this was the final notice.  I called back, phone rang over 2 minutes before anyone picked up, there where on options as to why you are trying to reach IRS and when someone finally answered there was a bunch of noise in the background like in telemarking. This is defiantly a SCAMMMM.  When I tried to call back a second time phone rang for 5 minutes, no option to for "0", no option to leave voice and they did not answer.

Got a call from this number today, since I didn't recognized I just let it rang. Finally, they left me an auto voicemail saying that the IRS was filling a lawsuit against me and this was the final notice. So, afterwards I just blocked the number.
If the IRS has a problem with you, they WILL NOT call you, they send an official notice or letter thru the mail. Note that the IRS will never: 1) call to demand immediate payment, nor will the agency call about taxes owed without first having mailed you a bill; 2) demand that you pay taxes without giving you the opportunity to question or appeal the amount they say you owe; 3) require you to use a specific payment method for your taxes, such as a prepaid debit card; 4) ask for credit or debit card numbers over the phone; or 5) threaten to bring in local police or other law-enforcement groups to have you arrested for not paying.
I hope this information is helpful.