Untested:

use File::Util;

unlink for grep { $_ =~ /xml$/i }
File::Util->new->list_dir('/your/directory', '--recurse');
[download]

Or alternately:

use File::Util;

$f = File::Util->new();

unlink for grep { $_ =~ /xml$/i } $f->list_dir('/your/directory', '--r
+ecurse');
[download]