MASSACHUSETTS (REUTERS) - Two people were stabbed at a shopping mall outside Boston on Tuesday evening (May 10) by an assailant who crashed a car into the front of a store after two other people were stabbed at a nearby residence, state police said.

The suspect was arrested at the Silver City Galleria after being shot by an off-duty law enforcement officer, Massachusetts State Police said in a statement.

The victims were taken to hospitals, state police said. Some of the injuries may be life-threatening. The suspect's condition was unknown.

Taunton Fire Department dispatcher Mike Marshall said reports started coming in around 6.37 pm and that the department sent out many ambulances.

Witnesses told local television station WHDH-TV that they saw people running out of the mall and heard gunfire.

The station reported that people in the area, about 40 miles (64 km) south of Boston, saw police officers with guns drawn and that the mall had been evacuated and put on lockdown.

The motivation behind the attacks was unclear. A number of state and local police units were at the crime scenes, authorities said.

Police said two people were stabbed at the mall after the assailant crashed a motor vehicle into the front of a store. The other two stabbings appear to have been committed at a home a few miles from the mall, state police said.

A representative of the mall, which has 125 stores, a 12-unit food court, restaurants and a cinema, could not immediately be reached.