Safari pop-up of a malicious attack
I received a pop-up in Safari that my Mac has been attack maliciously and it is now being monitored. It also said to call Apple at a given number. I, obviously, did not call. It also froze Safari. I did a force quit, rebooted and the problem was gone. Should I be concerned?
MacBook Air (13-inch Mid 2013), OS X Yosemite (10.10.5)