At about the same time, British Field Marshal George Milne was tasked by the allies with devising a solution to Italian and Greek tension in the Menderes River Valley. Milne warned in his report that Turkish guerrilla action would continue as long as the Greeks continued to occupy Smyrna and questioned the justification for Greek occupation. Most importantly, his report developed a border that would separate the Smyrna zone from the rest of Anatolia. The council of Great Britain, France, U.S. and Italy approved the Milne line beyond which Greek troops were not to cross, except to pursue attackers but not more than 3 km beyond the line.