Killing wall and walling in same turn

Can I kill my opponents 3-unit-wall around his city, & make a wall of my own around his aforementioned city in the same turn?

This is mostly a situation based thing, if people you know who will do this do this, you can both prevent it and both know youre doing it its a legit tactic, otherwise ur a dirty player because we all know we not supposed to do this

The amount of units you need to do that, despite the risk that you will fuck it up half the time is enough punishment.