ANKARA, June 6 (Reuters) - Turkish troops conducted a "limited operation" into northern Iraq in recent days in pursuit of Kurdish rebels, a military official said on Wednesday. "This cannot be called a cross-border operation, it is a limited operation," said the official, speaking on condition of anonymity. The official noted it was not unusual for troops to make "hot pursuit" raids across the mountainous border into Iraq, where an estimated 4,000 rebels of the outlawed Kurdistan Workers Party (PKK) are believed to be hiding.