Over 80 countries pledging to destroy their stockpiles of cluster bombs met in Berlin, but several major nations that have spurned an international ban stayed away.
"Cluster munitions are among the most problematic and vicious types of ammunition used in contemporary warfare. The long-term effects of their use are disastrous," German Deputy Foreign Minister Gernot Erler said.
"We see a new momentum in nuclear disarmament, and commend our American partners for their new approach. Let us hope ... that this momentum will also be extended to conventional disarmament."
A cluster bomb is a weapon fired by artillery or dropped by aircraft that splits open and scatters multiple - often hundreds - of smaller submunitions, or bomblets, over a large area.
Often many of the bomblets fail to explode immediately and can lie dormant for many years, killing and maiming civilians - a quarter of them children, campaigners say - long after the original conflict is over.
First employed by the German Luftwaffe on the English town of Grimsby in 1943 and by the Red Army the same year, their use took off in the US bombing of Vietnam, Cambodia and Laos in the 1960s and 1970s.
More than three decades later, 300-400 people are killed in Laos every year by the 80 million submunitions estimated to be still undiscovered, said Laotian deputy Foreign Minister Bounkeut Sangsomsak.
"In the past 20 years we have cleared only 0.02 per cent of the contaminated land. It's not going to take centuries, but a thousand years," he said.
Most recently they were deployed by both sides in Georgia's 2008 war with Russia, rights groups say, in Israel's bombardment of southern Lebanon in 2006, and by the US and its allies in Iraq in 2003 and in Afghanistan in 2001-02.
They were also put to deadly effect by Nato in Serbia in 1999, by the British in the Falkland Islands in 1982, during the Balkan conflicts of the 1990s, by Ethiopia and Eritrea, and by Morocco and Sudan, campaigners say.
According to a 2006 report by Handicap International, there have been at least 11,000 recorded and confirmed post-conflict casualties and the actual number - levels of reporting being low - may be as high as 100,000.
Last year around 100 countries, including Britain, France, Germany, Australia and Japan, agreed to ban the use, development, production, transfer and stockpiling of cluster bombs, creating the Convention on Cluster Munitions.
Ten countries have since ratified the CCM. Once 30 have done so - as campaigners hope they will by the end of this year, the treaty comes into force, giving the 98 signatories eight years to destroy their stockpiles.