ANKARA, Oct 9 (Reuters) - Turkish Prime Minister Tayyip Erdogan gave the go-ahead on Tuesday for all necessary measures to be taken against Kurdish rebels, including a possible incursion into northern Iraq where many are hiding. "The order has been given for every kind of measure to be taken, including if needed a cross-border operation," Erdogan's office said in a statement after a meeting of senior officials following a series of devastating rebel attacks which have claimed the lives of 15 Turkish soldiers since Sunday.