The International Red Cross sounded the alarm at the UN conference on sustainable development here Thursday about the damage caused by unexploded munitions and other weapons.

"Unexploded munitions and other explosive remnants of war kill and maim in cities and countryside, while wreaking havoc with economic and social development," the International Committee of the Red Cross (ICRC) said.

"Weapon contamination constitutes an ongoing security threat to entire communities. It prevents people from cultivating their fields and cuts them off from food and clean water," said Felipe Donoso, head of the ICRC's unit for Argentina, Brazil, Chile, Paraguay and Uruguay.

The ICRC said this was the case in 40 percent of the countries in which it operates, including Libya "where explosive remnants of war are preventing people from returning to their homes and delaying post-conflict reconstruction."

The agency said it has destroyed or neutralized over 6,500 explosive devices in Libya since early 2011. Together with the Libyan Red Crescent, it also runs awareness-raising programs in the country.

In South America, the issue is particularly acute in Colombia, wracked by decades of civil strife.

Last year, the ICRC launched prevention campaigns in more than 20 countries, including Azerbaijan, Bosnia, Cambodia, Ivory Coast, Eritrea, Iraq and Nepal.

In some cases, ICRC teams remove unexploded munitions to ensure that essential buildings and infrastructure, such as hospitals, schools and water-pumping stations, can be used safely.

The organization has also set up a unit in charge of collecting information on the dangers facing people in affected areas and carrying out awareness-raising programs to reduce those dangers.

The contamination is caused by unexploded munitions such as grenades, mortars, artillery shells, cluster munitions , bombs and rockets.

Over the next 10 days, the ICRC is holding a photo exhibition here to highlight the issue and is giving a presentation on "the consequences of weapon contamination for sustainable development".

The UN conference dubbed Rio+20 because it comes 20 years after the Earth Summit opened Wednesday.

It will climax with a June 20-22 summit that is to draw 116 world leaders to discuss prospects for a green economy that can reconcile economic growth with poverty eradication and environmental protection.