A German archaeologist said he has found relics of "humanity's first war" in northeast Syria in the form of clay balls used as ammo almost 6,000 years ago. "We have there the oldest example of an offensive war," Clemens Reichel, who is leading an archaeological dig in the ancient city of Hamoukar, on the border with Iraq, for the University of Chicago U.S. Reichel said that the city, whose fortifications were three metres thick, was besieged and reduced to ashes probably by attackers from southern Mesopotamia. "It was not a little skirmish which took place here," said Reichel. He spoke of a real "combat zone", to which the some 2300 balls of clay discovered at the main part of the site bear witness.