LONDON — Six people, including two children, were killed on Sunday following a knife attack at an apartment on the Channel Island of Jersey, police said.

A 30-year-old man has been arrested.

Officers were called to an address in Saint Helier, the island's main city, at around 3:00 pm (14:00 GMT) after reports of a multiple stabbing, States of Jersey Police said.

Five people were found dead at the Victoria Crescent address. A sixth person, critically wounded, was to Jersey Hospital but died following surgery.

The victims were two children, two women, and two men and they were all Jersey residents, police said.

Police immediately set up a major incident room at the St Helier headquarters and several witnesses have already come forward.

Head of crime services Stewart Gull said: "Clearly this complex investigation is in its very early stages as we try to establish exactly what happened.

"We are appealing to anyone who may have any information to contact us.

"We are mindful, too, of the impact of any such serious and tragic incident on the local community, and we have police officers in the area to support the investigation and local people," added the inquiry leader.

Local resident Andre Thorpe said four or five police cars were at the scene.

"I saw police come running out with a child, it was a small child, I just saw the legs. They went off in an ambulance," he said."

"When the paramedic came back her shirt was covered in blood."

Thorpe said he understood that all the victims were from the same family.