People in County Down have been advised to keep their windows and doors closed over what the police have described as a suspected chemical leak.

Three fire appliances are at the scene on the Steps Road in Magheralin.

The Northern Ireland Fire and Rescue Service (NIFRS) said it was dealing with a "hazardous incident involving gas" and advised people to avoid the area.

The road has been closed in both directions. Police have asked motorists to seek an alternative route.