A police officer and at least five other people have died in a series of gun battles in Jersey City, in the US state of New Jersey.
Two other police officers were wounded during the incident, which ended in a shootout after two gunmen barricaded themselves in a kosher supermarket.
A motive for the incident is not yet known. But the mayor said investigators believe the location was “targeted”.
Several local schools and businesses were also put on temporary lockdown.
Authorities identified the police officer who died as Joseph Seals, 39, who was part of a state-wide programme to confiscate illegal weaponry.
Speaking to reporters, Jersey City Police Chief Mike Kelly said Mr Seals was a “leading police officer in removing guns from the street”.
How did the attack unfold?
Mr Kelly said violence first erupted at a cemetery just after 12:00 local time (17:00 GMT) on Tuesday. Local media reported that confrontation between police and the suspects was linked to a murder investigation, but this has not been confirmed by authorities.
Police at the scene immediately came under “high-powered rifle fire”, Mr Kelly told reporters, and it is believed that Mr Seals was killed while approaching the two suspects, who have not been publicly identified.
The pair fled the scene in a van and took shelter in a kosher supermarket where they held off armed police and federal officials for four hours, shooting off hundreds of rounds of ammunition.
Investigators believe the two gunmen killed three people in the shop before they were shot dead. At least one survivor from the shop is being treated for injuries.
Mr Kelly said investigators also believe the suspects’ van contained an “incendiary device” which was removed and taken away for examination by police disposal specialists.