ROME (AFP) - A 48-year-old man shot dead four people, including a police officer, and injured six others after opening fire from his balcony in Naples, police said.

"The toll is four dead, including a lieutenant in the municipal police who was a neighbour of the shooter and was the first to intervene," a police spokesman said.

"We found two victims on the balcony, we presume they are members of his family but they did not have documents on them to allow us to identify them immediately.

"The fourth victim is a civilian who was passing in the street," he said.

The gunman surrendered to police after the shooting.

Four of the six people injured were police officers who had been called to the scene.

Italian media reported that the shooter had initially barricaded himself into his flat after a dispute with his wife and had been threatening to explode gas cannisters.