Q: Is 1-808-725-3292 a valid toll free number to contact the mac support team?

I have an imac 27" with Lion OS.

Just got a security threat warning from "mac support team" noting error code UR97L1DA2TA and to call mac support at 1-808-725-3292 in order to scan and resolve potential threats to my personal & financial info.

The warning (written & audio) has caused my imac to lock up!

Is this warning for real?  Or a scam?

o