By Stephanie Holmes BBC News

Clearing land of mines is a painstaking process

The international agreement, now signed by 156 states, is hailed as a rare success.

It is credited with having established a global norm which has made the use of such mines unacceptable practice.

In 2006 alone, more than 450 sq km of land was cleared of mines.

And although 5,751 people still died in landmine-related incidents, this was lower than in previous years.

"It has achieved almost as much as it had the potential to achieve," Tamar Gabelnick, Treaty Implementation Director for the International Campaign to Ban Landmines (ICBL), told the BBC News Website.

Yet the treaty has not been an unmitigated success. Some states, including Russia, Burma and Korea continue to use landmines, as do armed rebel groups and militias in 10 countries.

There are also countries that, while they may not use landmines, have refused to sign up to the treaty. These include the US, China, India, and Pakistan.

Military function?

Ms Gabelnick describes the landmine as a "flawed weapon" because it cannot differentiate between a civilian and a soldier.

Children are some of the most frequent victims of landmines

"It's not like a gun. The soldier has an opportunity to say, 'Here comes an enemy soldier, I press the button and I target that soldier,' and that's war," she said.

"What is not war is letting the weapon lie there for whoever happens to come along and set it off first."

But the US argues that the anti-personnel mine still has a military function on the battlefield, protecting high-risk areas such as borders, convoy routes and weapons depots.

The US military hopes to develop mines that can be de-activated once a conflict has ended, and reserves the right to use them.

Walking the line

"We believe mines can and do have a military utility which is not bounded by geography," said Richard Kidd, the US Acting Deputy Assistant Secretary of State.

"But given that, the question is: how can we make them as safe as possible?"

He defends the US choice to not sign up to the Mine Ban Treaty, also known as the Ottawa Convention.

"We were faced with a formulation of the treaty that forced us to choose between signing the treaty and meeting our military commitments to allies. We chose our military commitments," he said.

We, as the US, are not going to clear the million dollar mine on top of a mountain or in the middle of the jungle Richard Kidd US State Department In pictures: Afghan mine clearance

He argues that the US' own policy goes far beyond the limitations of the treaty, which he says is too narrowly focused.

"We have made a commitment to leave no mines of any type on any battlefield in the world, a commitment that has not been made by any other major power," he said.

"We are not limiting ourselves to any one munitions type. We are saying if there is an impact we should treat that regardless of whether that impact is a landmine, unexploded ordnance, AK47 or a weapons dump."

He says that the focus on landmines exclusively is misplaced as they cause just a fraction of the total number of munitions-related casualties.

'Million dollar mine'

Yet, he argues, from beyond the strict confines of the treaty, the US has been leading the way in efforts in de-mining efforts, contributing some $1.2bn - almost a third of total funding - since 1993.

The US says it is investing money in safe mines that can be de-activated

"Were it not for the US one-third more mine fields would be out there," Mr Kidd says.

But while welcoming this contribution, the ICBL criticises the US for failing to help countries remove each and every known mine on their territory - as they are obliged to do under the treaty.

It's an argument that the US regards as absolutist.

"We, as the US, are not going to clear the million-dollar mine on top of a mountain or in the middle of the jungle. Instead we will use that money to help victims from small arms and weapons," says Mr Kidd.

Ms Gabelnick counters that the only way to be mine-safe is to be mine-free.

"There might be mines along a border that nobody is using today, but tomorrow there could be a refugee crisis," she says.

Jody Williams, whose leadership on landmines won her a Nobel Prize, argues that there will always be a fundamental difference between thinking militarily and thinking morally.

"Militaries have never met a weapon they didn't like," she says.

"One can argue the military value of any weapon - even a nuclear bomb - but does that make it moral? No.

"In a democratic society it is not OK to use any weapon to get the job done."