Police operation underway on Charles Street Parramatta, following a shooting. Courtesy Channel Seven.

Two dead and one officer injured in an shooting outside Parramatta Police Headquarters

POLICE denied having previous warning of a possible attack on the Parramatta headquarters ahead of today’s deadly shooting that saw a lone gunman shoot dead a police IT worker before being gunned down by officers.

The shooter, dressed in black, launched an attack from Charles St at 4.30pm (AEST), peppering the front of the building with bullets.

He shot a police IT expert before being gunned down by special constables who guard the entrance, The Daily Telegraph can confirm.

In a statement police said the special constable shot the gunman after a person had been killed.

“It appears an officer has discharged his weapon, responding to a report that a person had been shot,” it said. “Two people have died at the scene.”

A critical incident team will now investigate the circumstances surrounding the incident which took place near a childcare centre used by police.

NSW Police commissioner Andrew Scipione remains inside the Parramatta headquarters with his three deputies and is being briefed by investigators.

“(The employee of the NSW Police Force) was simply leaving work,” Commissioner Scipione said.

The victim’s relatives have not yet been informed, so his name has not yet been released.

“The identity of the gunman is not yet known,” Commissioner Scipione said.

He said they cannot speculate on motive at this stage.

“There is no threat that we are dealing with that hasn’t been resolved here,” he said.

When asked if he believed the officer had been directly targeted, Commissioner Scipione replied, “Yes.”

Children were earlier locked inside the centre as police investigated the crime scene.

Father Dennis Entriken told The Daily Telegraphthey all hoped their kids had been spared the sight and sounds of the horror.

“Unfortunately the children are still inside - we can’t get access to them and they can’t come out,” he said.

“Because one of the bodies is quite literally on the ground at the entrance to the childcare centre.”

The children have since been reunited with their parents.

Earlier, a local real estate agent Edwin Almeida told radio 2UE that he saw a man wearing a black robe brandishing a gun in the air.

“One of our real estate agents went outside to have a look and ran back in saying there was a guy wielding a gun and shooting at people in the street,” he said. “We looked through the window and there was a man in a black what looked like a gown laying on the floor just outside the NSW police headquarters.

“The guards were pointing guns at him.”

The Channel 7 chopper told Ben Fordham’s 2GB radio program that two people had been shot and that there were two bodies on the ground covered in sheets in Charles St.

Following the incident, members of the public in the nearby Commercial Hotel, in Hassall St, were told to stay inside the pub.

Ambulance officers were called to the scene at 4.35pm.

Finance worker Rizwan Shaikh, who lives in an apartment opposite police headquarters, told The Daily Telegraph he heard the shooting.

“I finished work and was in the shower and I heard the gunshots,” he said.

“I heard six or seven gunshots and it was pretty loud.”

BREAKING: Caller Edwin tells me he just witnessed a shooting outside the NSW Police headquarters in Parramatta. Here's what he caught on camera. Posted by Justin Smith on Friday, October 2, 2015

The shootings in #parramatta happened directly outside a daycare centre used by police force families. — Peter Hinton (@peterjhinton) October 2, 2015

UPDATE: Two armed men walked into police station at Parramatta and were reportedly shot dead. #9News — Nine News Sydney (@9NewsSyd) October 2, 2015