Queensland police are negotiating with a gunman who allegedly shot and killed a police officer west of Brisbane on Monday.
Police identified the officer as father-of-two, Senior Constable Brett Forte, and expressed their gratitude for his 15 years of service to the Queensland Police service.
Forte was shot during a traffic stop in the Lockyer Valley just before 2pm. The stopped man had been wanted by police.
A police source told AAP the man was believed to have been armed with a machine gun.
Police pursued the man and it is understood a police vehicle rolled over during pursuit.
The offender also fired at a police helicopter while entering a farmhouse where he has remained holed up, AAP reported.
"We have a person contained and at my last advice we were negotiating with that person," Commissioner Ian Stewart said at a media conference on Monday evening.
In announcing Forte's death, Assistant Police Commissioner for the Southern Queensland Police Region, Tony Wright said: "It is with great sadness that I announce the death of a serving police officer, Senior Constable Brett Forte from the Tactical Crimes Squad.
"At approximately 2 o'clock this afternoon, police observed a person of interest. The person of interest drove down the range from Toowoomba, police followed him into an area, the person of interest alighted from his vehicle away from where the police officers were and opened fire on the police vehicles.
"Unfortunately in this time, Brett Forte lost his life. Other police officers were able to remove Brett away and extract themselves from the scene."
Commissioner Stewart also commented on the tragic death, saying "We will miss Brett deeply" and that authorities are now looking towards resolving the matter by apprehending the suspected gunman.
"Today is a very very sad day for the Queensland Police Service. We've lost a fine officer and our condolences and thoughts and love are with his wife, his children, his family and of course his colleagues," he said,
"We will miss Brett deeply and our job now is to make sure that we resolve the current operational issue without further loss of life and certainly that operation is ongoing."
Earlier, Queensland Police confirmed in a statement that an officer was injured in the Lockyer Valley at Seventeen Mile, just outside Toowoomba, around 2:20pm before later dying.
"The Queensland Police Service can confirm the death of a male officer who was involved in a shooting incident whilst on duty in the Lockyer Valley today," the statement said.
Earlier, police locked down the area, saying "the incident is still unfolding". Members of the public were being advised to avoid the area surrounding Wallers Road, Forestry Road, Ringwood Road and Fords Road.
"An armed man remains outstanding and specialist police are responding. Local residents are being advised to remain inside," police said.
"An exclusion zone remains in place for the area of Fords Road, Forestry Road West, Sandy Creek Road, Gerard Lane, Seventeen Mile Road, Wellers Road and Forest Road," police said.
"Residents living in the exclusion zone are being advised to remain inside their homes until further notice."
A Queensland Police Union representative, Ian Leavers, told media the death is a "tragedy" and described the officer as "a family man who was respected by all of his colleagues".
"One of our colleagues was murdered this afternoon by simply trying to apprehend an offender, It is a tragedy.
"He was a decent person, a family man who was respected by all of his colleagues. His family are being supported are as his work colleagues at this point in time.
"At this time, our thoughts are with his family and those other close family members who are still en-route to Toowoomba."
Queensland Premier Annastacia Palaszczuk also offered her condolences for the family and friends of the officer in a statement.
"My thoughts and prayers are with the family and friends of the officer killed while carrying out his duties protecting our community in the Lockyer Valley today," she said.
"Every day, the brave officers of the Queensland Police Service put their lives on the line when they go to work. Each of us should be immensely grateful for the work they do."
Queensland Minister for Police called the officer "a hero" in a statement and paid tribute to his service.
"My thoughts are with his family, friends and colleagues of the Queensland Police Service officer who was tragically killed this afternoon while doing his job selflessly serving the people of Queensland," the statement said.
"Along with millions of Queenslanders, I pay tribute to his service."
Anyone with information is asked to contact police on 131 444 or to Crime Stoppers on 1800 333 000 or via crimestoppersqld.com.au.
Click below to follow HuffPost Australia Politics on Facebook!
ALSO ON HUFFPOST AUSTRALIA