Three people have been arrested and at least one more person is still in a standoff with the police Armed Offenders Squad in Palmerston North.
The incident began at Pioneer New World on Main Street earlier this afternoon when a man threatened a customer.
The man, along with a number of other people involved, then moved to a house near the corner of Church St and Botanical Rd, about ten minutes' walk from the New World supermarket.
Police set up a cordon around the house and a standoff ensued, resulting in the arrest of three people.
A police cordon around the New World has now been lifted, but the cordon around the Church St house is still in place.
Police are asking anyone who was at Pioneer New World and who may have seen the incident to come forward.