A BROTHER of one of the Australian soldiers killed in Afghanistan this week says he was "just such a top guy".

Gary McDonald, whose brother, Lance Corporal Mervyn McDonald, died with Private Nathanael Galagher when their helicopter crashed in Helmand province, told ABC radio that "we never thought it would actually happen to us".

"But we're just very proud of him and just hope people understand what's going on over there and why he was over there.

"He actually just sent us a postcard earlier this month about how things were going.

"He showed us footage of what he was doing, how he trained and flew in on his helicopters.

"Mervyn was a hell of a guy, he was. Would always do things for you. He was always sending stuff to my kids.

"He really wanted to start a family. He's a very big family person... we just can't believe he's gone.

"He had a heart of gold. He was always trying to make sure that we were OK. He was just such a top guy.

"He was just always one of those people who'd always pick you up and help you and just... make sure you knew he was there.

"But now he's not there... so he's going to be surely lost by all of us.

"I just want him to be remembered."

Meanwhile, Prince Charles has sent condolences to the families of the five soldiers killed in Afghanistan, saying he was utterly horrified to hear the news.

In a message sent to Prime Minister Julia Gillard and Governor-General Quentin Bryce, the Prince of Wales said he could begin to imagine the anguish for the families because his own sons - Prince William and Prince Harry - served in the British armed forces.

"My wife and I were utterly horrified to hear of the tragic deaths of five Australian soldiers in Afghanistan in the same day. As the father of two sons serving in the Armed Forces, I can perhaps begin to imagine the anguish being suffered by their loved ones. Our hearts go out to them at such a desperately impossible time," the message says.

"I know how profoundly the entire ADF and, indeed, all Australians will grieve at this unspeakable and terrible loss. I should be grateful if, on behalf of my wife and myself, you could convey our deepest and most heartfelt sympathy to the families of those who lost their lives in these terrible incidents.

"You are all so much in our thoughts and prayers at this particular time.''

Defence chief David Hurley today said Private Galagher, 23, was from Wee Waa in NSW, and Lance Corporal McDonald, 30, was from Carnarvon in Western Australia.

Lieutenant General Hurley said Private Galagher enlisted in the army in 2007. He was on his second deployment to Afghanistan.

"He is survived by his partner, parents and sister,'' General Hurley said.

Lance Corporal McDonald enlisted in the army in May 1999. He served for five years, left in 2004 and then re-enlisted in 2005.

He was deployed to East Timor and was on his sixth deployment to Afghanistan.

Corporal McDonald is survived by his fiancee, his mother and stepfather and three brothers,'' General Hurley said.

The families of three men killed in an insider attack by a member of the Afghan National Army are not yet ready to have their personal details released.

The three soldiers, from the Australian Mentoring Task Force Five, were from Brisbane regiments based at Enoggera's Gallipoli Army barracks.

They were stationed at a patrol base in the Baluchi Valley, north of the main base at Tarin Kowt.

Speaking at the barracks today, Commander 7th Brigade, Brigadier Greg Bilton, passed his condolences to their families.

"This takes the brigade's casualties to 11. The brigade is in shock," Brigadier Bilton said.

"We are working with the families who still have the task of telling their extended family."

Brigadier Bilton reminded the community that the soldiers who remained in hospital needed support.

"We will complete our mission," he said.

The five deaths made it the worst day of combat losses since the Vietnam War.

General Hurley said Sgt Hek Matullah, the man believed to be responsible for shooting the three diggers and wounding two others, arrived in Oruzgan province in mid-July, after completing induction training in Kandahar.

"We are not yet aware of any relationship he has with the Taliban,'' he said.

As well as an Australian investigation into the incident, Afghan national security forces have also established a joint team with international forces to conduct its own investigation.

General Hurley said all Australian personnel had now adopted "enhanced force protection measures, including some relocations''.

He added: "Today and tomorrow are normally days of lulls in activity being Friday - a day of prayer for the Islamic religion.

"That gives us a bit of time to reset for the coming week.''

General Hurley said the Taliban had claimed responsibility for all insider attacks - also known as green on blue - in Afghanistan.

"The evidence does not necessarily support this," he said.

"But regardless of these motives, these attacks will be used by the insurgency to undermine our confidence and our relationship with the ANSF."

The relationship between Australian and Afghan soldiers was based on trust, which was hard to build and maintain, the general said.

"This most recent incident has challenged that trust," he said.

"We will continue to work with our Afghan partners to strengthen our relationship and improve their capability."

General Hurley said he had spoken with International Security Assistance Force (ISAF) chief General John Allen yesterday and he would be in contact with him again today.

"It is fair to say that there is a range of emotions in the ADF today," General Hurley said.

"That's understandable in the circumstances."

But he said advice from Australian commanders on the ground in Afghanistan should give reassurance.

"They say that there is a positive relationship in the operating basis," he said.

"The members of the Afghan National Army share our sense of outrage at this attack.

"The ANA has been proactive... and is actively working to capture Hek Matullah."

Ms Gillard said withdrawing troops now would create a security vacuum because Afghanistan was not yet ready to step up to provide its own security.



She said the plan was still to withdraw most troops in 12 to 18 months.



"We're literally dealing with matters of life and death for our troops in the field and I'm not going to get sidetracked or waylaid into domestic Australian debate even if some ugly language has been used during the course of it,'' she said.



Ms Gillard said the nation was in shock, sadness and grief about the deaths of the five Australian soldiers.



General Hurley said security had been stepped up but no one could give a 100 per cent guarantee there would not be any more insider attacks. He said it would reward the enemy to cut short the mission.



"If we blink, the Taliban win,'' he said.



Ms Gillard used the same words: "If we blinked then we would be handing a strategic victory over to the Taliban.''



"After all that we have been through, and all that we have lost and all that we have done in Afghanistan, I cannot countenance leaving before the mission is completed, and I can not and will not countenance giving a strategic victory to people who have made it their work to kill Australians.''

PM 'has blood on her hands'

Independent MP Andrew Wilkie today said Prime Minister Julia Gillard and her predecessors have blood on their hands over the deaths.

Mr Wilkie said the tragedy of the deaths was amplified by the fact “none of these men had to die”.

He said Australia should no longer be in Afghanistan, as it was not in the nation’s interests.

He said if previous prime ministers John Howard and Kevin Rudd had not committed soldiers, or withdrawn them while in office, the soldiers would not have died.

“Or if Julia Gillard had withdrawn our soldiers from Afghanistan when she came to power those soldiers would not have died,” he said.

“The five soldiers who died in Afghanistan this week died unnecessarily and Howard, Rudd and Gillard all have blood on their hands.”

'Green-on-blue' attacks on the rise

Seven Australian soldiers have now been killed in three so-called "green on blue" or "insider attacks" in the past 16 months by suspected Taliban posing as Afghan soldiers in training.

Defence Minister Stephen Smith said the motive of the Afghan soldier who shot dead three of the Australian Diggers may never be known, but responsibility will almost certainly be claimed by the Taliban.

Mr Smith said this morning that the Afghan National Army (ANA) vetting process was aimed at minimising the threat of infiltration.

"Sometimes the motivation is one of personal disgruntlement, sometimes the motivation is an ideological one and sometimes the motivation is just a clash between individuals," he told reporters in Perth.

So what was the motivation on this occasion?

"It's too early to tell and we may never know," the defence minister said.

Afghan soldiers have turned their weapons on Australian soldiers on four occasions - three last year.

The first time, on May 20 last year, Afghan soldier Shafied Ullah shot dead Lance Corporal Andrew at a patrol base in the Chorah Valley.

In October, Afghan soldier Lieutenant Darwish Khan shot dead Captain Bryce Duffy, Corporal Ashley Birt and Lance Corporal Luke Gavin at a patrol base in Kandahar Province.

Then in November 2011, Afghan soldier Mohammed Roozi shot and wounded three Australians.

In the latest incident, ANA Sergeant Hek Matullah shot dead three Australian soldiers and wounded two.

Mr Smith said it had proved very difficult to determine the motivation behind the earlier attacks.

Ullah escaped but was subsequently shot dead when he resisted arrest by US forces. Khan was shot dead on the spot.

Roozi escaped and later appeared in a Taliban propaganda video, claiming he killed 12 Australians.

It remains unclear if he was a Taliban plant or acted for his own reasons and was subsequently welcomed by insurgents.

"Our experience has been the same as our NATO and International Security Assistance Force colleagues. It is difficult to get a true insight into motivation," Mr Smith said.

"And we can't discount the prospect or the possibility or the potential that it may happen again, either to us or to our NATO or ISAF colleagues."

Earlier today, a US defence analyst said the surge in so called "Green on Blue" attacks was a troubling sign of the gathering strength of the Taliban.

Bill Roggio, Senior fellow for the Foundation for Defence of Democracies, said it was highly probable that the Taliban had made a concerted effort to infiltrate and coerce members of the Afghan National Army.

Speaking the The Courier Mail from America this morning, Mr Roggio said the tactic was linked to announcements of the drawing down of troops by a variety of countries involved in the conflict.

"I think the Taliban have made a concerted effort to infiltrate and coerce members of the military, absolutely," he said.

Mr Roggio said it was possible Afghan soldiers were being threatened by members of the Taliban to organise or directly participate in the killings.

But he also suspected that after decades of war, many of the locals could see the writing on the wall, and were now throwing their lot back in with the Taliban.

The western commitment to Afghanistan was not seen as strong enough, he said, and with the troop draw downs they sensed the Taliban was on the ascendancy.

Mr Roggio said he doubted the situation could be improved, even if there was strong statements of renewed commitment from western powers.

"I think the horse may have left the barn," he said.

The Foundation for Defence of Democracies calls itself a non-partisan institution focusing on national security and foreign policy.

International Security Assistance Force spokesman Major Adam Wojack this morning confirmed the latest gunman was a sergeant by the name of Hekmatullah, or Hek Matola.

He said local authorities in Afghanistan were now hunting the gunman, who had worked as a guard at the Wahid Patrol Base in Oruzgan province.

"We do know that he acted alone, he was a single shooter ... he did kill those Australian soldiers then jumped over a fence and fled on foot," he told ABC Radio this morning.

Australia must stay the course in Afghanistan

Opposition Leader Tony Abbott today said he expected local authorities would be "relentless" in finding the man.

"Obviously the Australian forces in Afghanistan will be doing everything they can to punish this individual," he said.

Mr Abbott warned Australia could not shirk its responsibilities.

"I don't think Australians want us to be a country ... that cuts and runs," he told the Nine Network.

As Prime Minister Julia Gillard jetted back into Canberra after cutting short her Pacific Islands trip short, Mr Abbott insisted Australia had to stay the course in Afghanistan and finish the transition period over the next 18 months.

Federal Environment Minister Tony Burke said an Australian presence in Afghanistan was in the national interest.

"We do need to remember why we are there in the first place," he told the Seven Network this morning.

"The Taliban had become a hotbed and a home for terrorism networks around the world, including networks that were killing Australians.

"We do need to stay the course here to make sure we can leave an Afghanistan capable of defending itself.

"The transition out ... we are already in the phase now."

Shadow Treasurer Joe Hockey said the killer needed to face justice for his actions.

"This is evil, what they did was commit murder. This guy committed murder against three Australians. He needs to be hunted down and brought to justice," he said.

But it was important to deal with the facts, he added.

"The Afghan army are copping most of the casualties... not us," he said.

"That's the way it should be. We're training them."

Australian Greens senator Scott Ludlam said the attacks on Australian soldiers were targeted at morale.

"I have no doubt it will strengthen the resolve (of Australian soldiers)," he told ABC radio this morning.

Late yesterday, Prime Minister Julia Gillard implored Australians to show resolve.

"This is our single worst day in Afghanistan. Indeed, I believe this is the most losses in combat since the days of the Vietnam War and the battle of Long Tan," Ms Gillard said.

With tears welling in her eyes, Ms Gillard said the truly shocking news felt "like a physical blow" and she immediately cut short her visit to the Cook Islands, where she was attending the Pacific Island Forum. She will today meet military chiefs in Canberra to review security for the 1550 troops in Afghanistan.

With Australia's death toll in Afghanistan now at 38, Ms Gillard, who has visited Afghanistan twice and attended the funerals of 19 soldiers, said Australians would be justified in questioning the war but there would be no early exit.



- with Phillip Hudson, Steven Scott and Samantha Healy

