The soldiers, who were said to have been wearing Arab headdress, were accused of firing at Iraqi police when stopped at a road block.
Arab soldiers fired upon Iraqi police 
Taking from context the police are fired upon by people in Arab headdresses. Difficult because picking things out of the description to make a conclusion 
( z1 fire :ARG0 ( z2 soldier :mod ( z3 ethnic-group :name ( z4 name :op "Arab" ) ) ) :destination ( z5 police :mod ( z6 country :name ( z7 name :op "Iraq" ) ) ) )