You've received a phone call from someone claiming to be with the IRS, where they are saying that you need to provide them with your social security number so they can resolve an issue with your...

You've received a phone call from someone claiming to be with the IRS, where they are saying that you need to provide them with your social security number so they can resolve an issue with your taxes. They tell you that it is urgent and that if you do not comply, you will be arrested promptly.

What is likely going on?