"In addition to insecurity, Iraqis live amidst one of the greatest concentrations of landmines, unexploded ordnance and other explosive remnants of war in the world," said a joint statement by the UN Development Programme and the UN Children's Fund.
"Explosive remnants of war contamination in Iraq is so widespread that several development programmes are being hampered," it added.
Marking the International Day for Mine Awareness, they warned that unexploded ordnance is "of higher risk to Iraqi children, who often mistake them for toys or harmless objects to play with.
"A quarter of Iraq's 565 unexploded ordnance victims assessed in 2006 were under 18," they said.
At least 55 million cluster bomb sub-munitions were dropped on Iraq in the past two wars, which would make the country "the world's most contaminated country with this deadly unexploded ordnance."
Since 2005, UN-supported activities have cleared millions of square metres (square feet) of southern Iraq, destroying 105,221 explosive items, including 15,793 cluster munitions, the statement said.
David Shearer, deputy special representative of the secretary general and humanitarian coordinator for Iraq, said explosive remnants of war "continue to damage lives and livelihoods.
"They inflict lifelong injuries, deny access to productive land and undermine freedom of movement, including for the delivery of humanitarian relief. We need to increase efforts to reduce the harm they cause, and treat their victims."
UNICEF Representative for Iraq Roger Wright was quoted as saying "the damage they inflict extends beyond the physical, restricting children's ability to go to school safely and enjoy a normal childhood. Comprehensive awareness and risk education is essential as their best defence."
© 2008 Agence France Presse