Two people have been killed and four injured in separate stabbings at a house and a shopping centre in the US state of Massachusetts.

The attacks happened yesterday evening in Taunton - about 40 miles south of Boston.

Police say the attacker - a 28-year-old man - was shot dead by an off-duty officer.

He is believed to have stabbed two 80-year-old women at a home in the city, before crashing his car through the front of a Macy's store at a local mall and stabbing diners in a restaurant.

A motive for the attacks remains unclear, but state police say they haven't found any links to terrorism.