How to split a string after the nth character in r

I am working with the following data:

District <- c("AR01", "AZ03", "AZ05", "AZ08", "CA01", "CA05", "CA11", "CA16", "CA18", "CA21")

I want to split the string after the second character and put them into two columns.

So that the data looks like this:

state  district
AR        01
AZ        03
AZ        05
AZ        08
CA        01
CA        05
CA        11
CA        16
CA        18
CA        21

Is there a simple code to get this done? Thanks so much for you help