(KUNA) -- Four gunmen, two were Arab nationals, were killed during clashes with Iraqi police forces in Tal Afar district northern Mosul, while unknown gunmen assassinated an international transportation director, an Iraqi police official said Thursday. The nationalities of the Arab gunmen were not revealed by Tal Afar Police Brigadier Najim Abdullah, who revealed the attack to reporters.Meanwhile, another Iraqi police source said that International Transportation Director at Rabia'a border checkpoint Hazim Zainal was gunned down at his working place near the Syrian borders by anonymous armed men.