Need to create admin user without capability to create user

I need to remove user related capabilities(such as ‘create_users’, ‘add_user’, ‘list_users’, etc…) of an admin user.

I tested the code below in an ‘init’ method.

global $current_user;
get_currentuserinfo();
$current_user->remove_cap('create_users');
$current_user->remove_cap('add_user');
$current_user->remove_cap('list_users');

But I found that still user is able to access interface for managing user(even after refreshing many times). Is there any solution other than creating new role for this?