president of the czech republic has banned the u.s. ambassador from prague castle following a public dispute over the former 's decision to attend a russian world war ii parade .
in response to the critique , president zeman said ambassador schapiro is no longer welcome in the prague castle , the seat of presidency .
under attack : ` we should be able to communicate with our friends and allies , ' sobotka added .
parliament 's lower house speaker , jan hamacek , said zeman demonstrated a lack of ` diplomatic thinking .