By Australia Correspondent Rachel Morton with NZN
Five Australian soldiers serving in Afghanistan have been killed in two separate incidents.
One incident involved three soldiers being shot and killed by a man wearing an Afghan National Army uniform and occurred in southern Oruzgan province. Two other men were also shot but survived and are currently recovery in hospital.
It is unclear if the shooter was a member of the Taliban who had infiltrated the army or whether he turned on them for other reasons.
The Australian forces returned fire on the man but he fled the scene and the army is continuing to search for him.
Two other soldiers died when a American Blackhawk helicopter crashed in Helmand province.
The pair were both SAS soldiers.
Australian Prime Minister Julia Gillard is cutting short her time at the Pacific Islands Forum and immediately return to Canberra following the deaths.
Ms Gillard is in the Cook Islands and had planned to meet with US Secretary of State Hillary Clinton before returning to Australia.
At a press conference at her hotel in Rarotonga, Ms Gillard said it was "the most awful news" for Australia.
"This is a very big toll ... This is our single worst day in Afghanistan."
She said many Australians would feel the weight of the soldiers' deaths.
Ms Gillard will be driven to the airport following the press conference to fly home.
She says she has explained the circumstances to Cook Islands Prime Minister Henry Puna.
Richard Marles, Parliamentary Secretary for Pacific Island Affairs, will represent Australia at the remainder of the forum.
Ms Gillard says she still has faith in the progress Australian troops are making in Afghanistan.
"Our strategy is well-defined, our strategy is constant, and we cannot allow even the most grievous of losses to change our strategy... We went there for a purpose and we will see that purpose through."
She said there have been a number of "green on blue" attacks in Afghanistan which have prompted increased safety measures to protect soldiers.
Insider incidents like this are "corrosive of trust" and difficult for Australian troops to deal with, she said.
Both incidents will be thoroughly reviewed.
The attacks bring the total number of Australian deaths in Afghanistan since 2002 to 38.
3 News/NZN