It happened at the Grove shopping centre in Lower Market Street on Thursday shortly before 9.30am.An unknown man approached the woman and tried to wrestle her handbag from her. However, he fled the scene empty-handed.It is understood the woman was stabbed in the incident.Police said that she received injuries to her head and arm.She was treated in hospital for injuries not believed to be life-threatening.Local SDLP Councillor Colin McGrath described the incident as a "callous attack" and appealed for anyone witnesses to contact police."It appears that this attack was against a woman who was going about her business at the local Post Office," he said."This type of attack in such a public place and during the day time in our Main Street is extremely worrying and totally reckless. My thoughts are with the victim and her family at this difficult time."Investigating officers are appealing for witnesses.