Police in Derry believe an attempted paramilitary style attack may have been prevented in the Hazelbank area of the city last night.
They're seeking information about what they are describing as an aggravated burglary.
Police say shortly after 9:30 last night, a number of masked men smashed the window of a house in the Derrymore area of Hazelbank. One of them was reported to have had a firearm.
A man in his twenties, who was inside the house at the time, challenged the men, and prevented them from entering the property. He was struck on the arm with what is believed to have been a hammer, sustaining a minor injury which did not require hospital treatment.
A woman who was also inside the house was uninjured.
Police say their enquiries are at an early stage, however, one line of enquiry is this may have been a paramilitary-style assault.
They're urging anyone who was in the area at the time and saw anything suspicious to contact detectives at Strand Road, or the independent 'Crimestoppers' service.