A balaclava-clad man was seen fleeing the scene of a suspected firearms incident which is under investigation by police.
Armed officers were called to a house in Huddersfield last night (Thursday) after reports of a window being damaged just before 8pm.
The incident on Wasp Nest Road is being treated as a "potential firearms discharge", West Yorkshire Police said.
A spokesman said: "Witnesses reported a male in dark clothing and a balaclava fled the scene shortly after the incident and ran up an alleyway between Wasp Nest Road and Cobcroft Road."
A police cordon remains in place this morning as witnesses are urged to come forward.
Detective Inspector Stephanie Fox, of Kirklees CID, said: “We are currently continuing with our investigation into this incident and gathering evidence to establish the full circumstances.
“We will be deploying additional police officers into the area to reassure the residents.
“I would urge anyone who was in the area last night and witnessed anything suspicious to come forward and speak to the police, as any information may prove vital for our enquiries.”
Anyone with information should call police on 101, quoting crime reference 13190070015, or Crimestoppers, anonymously, on on 0800 555111.