What is the minimum length of a valid international phone number?

Question

I need to validate user input of an international phone number. According to E.164, the maximum length is 15 digits, but I was unable to find any information about the minim

Answer 1

EDIT 2015-06-27: Minimum is actually 8, including country code. My bad.

Original post

The minimum phone number that I use is 10 digits. International users should always be putting their country code, and as far as I know there are no countries with fewer than ten digits if you count country code.

More info here: https://en.wikipedia.org/wiki/Telephone_numbering_plan