A Canadian military officer believed an ancient code of honour would protect himself and his colleagues when they sat down for a routine tribal meeting in an Afghan village.

But after witnessing an axe-wielding assailant attack his fellow officer, he feels he has been proven wrong.

Capt. Kevin Schamuhn says his faith in the unwritten rule of the shura, that a guest must be welcomed and protected, has been corrupted.

"Everything I've been taught about Islam, everything I've been taught about the Pashtun code of honour, has just completely been defiled in a horrifying way," Schamuhn told CTV's Lisa LaFlamme in Afghanistan.

Capt. Trevor Greene was conducting a shura, a meeting with village elders meant to promote peace, when a teenager pulled an axe from his coat and struck him in the head.

"I can expect someone shooting at me. I can expect someone throwing a grenade at me, as weird as that sounds ... I'm ready for that. But someone taking an axe and attacking someone like that ... that replays in our head," Sgt. Rob Dolson said.

Greene had removed his helmet as a sign of respect as he sat down Saturday to discuss reconstruction needs with elders in Shinkay, a village 70 kilometres north of Kandahar.

Soldiers routinely lay down their weapons and remove their helmets as a goodwill gesture. But it's a gesture the military is now re-evaluating.

When asked if he would take his helmet off again, "probably not," Dolson was quick to respond.

While the soldiers had been trained to engage the enemy at close range, the attack on their colleague was shocking all the same.

"Things slow down, events like that everything seems to be in slow motion but yet fast at the same time," Pte. Matt McFadden said.

But their shock was fleeting. Schamuhn and McFadden instinctively responded by firing their weapons and killed the teen.

"He attacked a Canadian soldier and that's all I thought of, we responded," said Dolson.

Canada's Task Force in Afghanistan said the man who attacked Greene was a Taliban insurgent.

However, an Afghan elder has reportedly disputed that claim, saying the attacker was a 16-year-old boy with no Taliban connections.

Haji Mohammed Eisah told The Associated Press that Abdul Karim was upset at the U.S.-led coalition's heavy-handed tactics and insensitivity to tribal traditions.

"You can't tell who is and who isn't ... Well they don't go running around with Taliban party cards that says they're Taliban. They could be anyone," Dolson said.

Meanwhile, the Canadian military is reviewing tactics in Afghanistan after its first week leading coalition troops ended with two soldiers killed and the axe attack.

Col. Tom Putt, deputy commander of Canadian forces in Afghanistan, says strategists are currently re-examining procedures involving driving habits and security measures for meetings with local leaders.

"Undoubtedly we are going through a process of understanding security," Putt told reporters. "We have to keep (meeting local leaders). It's how we do it that we don't know yet."

Col. Michel Drapeau, former director general for the Department of National Defence, said soldiers "learn some very hard lessons in the first few days or weeks of an operation."

"You're not quite sure which way the enemy is going to be acting. In this case, there's a psychological shift required on the part of the soldiers," Drapeau told CTV's Canada AM Monday.

"They've been trained for the past 50 years as peace keepers. Now they're into a war setting and they have to look at every individual they cross .. as a potential enemy."

With a report from CTV's Lisa LaFlamme