Regex to validate String with exactly 2letters followed by either 6 or 7 numbers

I want to validate UZB passport number and therefore I need regex.

So my requirements is that, string must contain exactly 2letters (not case-sensitive) followed by 6 or 7 numbers (not less, not more).

Examples:

1. Should pass: AB1234567 or aB123456
2. Shouldn’t pass: ABC123456, AB12345678 or A12345678

I tried

/[a-zA-Z]{2}[0-9]{7}$/

but it didn’t help.
Thanks in advance

>Solution :

Solution below:

^[A-Za-z]{2}\d{6,7}$