DARWIN, AUSTRALIA (WASHINGTON POST) - A gunman killed at least four people on Tuesday (June 4) in the northern Australian city of Darwin, and police arrested a 45-year-old man in the shooting spree, local media reported.

"At this stage, we've got reports of four deceased and a number of other people who have been shot," Northern Territory Police Duty Superintendent Lee Morgan told the Guardian Australia newspaper.

The Australian Broadcasting Corp reported that the suspect fired a shotgun at the Palms Hotel in the Darwin suburb of Woolner in the late afternoon.

Witnesses said the shooter opened fire in a number of rooms in the hotel before fleeing. Police said they arrested the suspect about an hour later.

They said he apparently acted alone and that no other suspects were being sought, the BBC reported.

The city centre was locked down for an hour after the gunman fled the scene of the shootings.

Prime Minister Scott Morrison told reporters that the attack was not linked to terrorism.

Speaking in London during a visit to participate in D-Day commemorations, Mr Morrison called the shooting spree "a terrible act of violence", but said there was "nothing to suggest" that it was "a terrorist act", the Associated Press reported.

Two people were taken to the Royal Darwin Hospital with gunshot wounds, and both were in stable condition, AP said, citing a Health Department statement.

Police responded to three crime scenes linked to the gunman in the capital of Australia's Northern Territory, ABC said.

A reporter for the broadcaster said she saw police tackle the suspect at a busy intersection and use a stun gun to subdue him.

"He shot up all the rooms and he went to every room looking for somebody and he shot them all up, then we saw him rush out, jump into his Toyota pick-up, and rush off," witness John Rose told the ABC.

It was the worst mass killing in Australia since September 2018, when five people were fatally stabbed or beaten in a house near Perth in western Australia.

Mass shootings have been relatively rare in Australia since the country enacted a strict gun-control law following a massacre in which 35 people were killed in Port Arthur, Tasmania, in 1996.

In March, a gunman attacked two mosques in Christchurch, New Zealand, killing 51 people in a massacre that prompted the government there to ban most semiautomatic firearms in the country.

An Australian anti-Muslim extremist was arrested in Christchurch shortly after those shootings and charged with multiple counts of murder.