GENEVA — Disarmament campaigners accused the United States on Wednesday of negotiating a treaty on cluster munitions which it says could encourage the use of the deadly weapon.

Negotiations began in Geneva this week among member states of the Convention on Certain Conventional Weapons (CCW) as they attempt to conclude a legally-binding protocol on cluster bombs.

The Cluster Munition Coalition (CMC) warned that if passed it could lead to an increase in the use of cluster bombs by countries not signed up to the Convention on Cluster Munitions, a ban which came into force in August 2010.

The United States is not among the 111 states who have joined the convention.

"An international convention with very high standards, comprehensively banning cluster munitions, entered into force a little over a year ago and yet we have governments here this week and next week negotiating a new international treaty on cluster munitions with much lower standards," said Steve Goose, editor of the Landmine and Cluster Munition Monitor.

"This has never happened before in international humanitarian law. We find it outrageous."

Cluster bombs split open before impact, scattering lots of smaller bombs over a wide area.

Goose said the draft supported by the US allowed countries to use cluster munitions made after 1980 and those with a less then one percent failure rate.

"We have a small group of states led by the US who are trying to provide themselves with legal and political cover to continue using the weapon," said Goose.

"If you have a specific new law that says it's okay to use some cluster munitions ... we think that will facilitate and might even encourage use."

At the opening of talks on Monday, head of the US delegation Phillip Spector said the text "offers the only chance of bringing the world's major cluster munitions users and producers ... into a legally binding set of prohibitions and regulations."

The CMC issued the warning at the launch of the Cluster Munition Monitor 2011 report, which noted two uses of cluster munitions in the last year -- by Thailand against Cambodia during a border conflict in February and by forces loyal to Moamer Kadhafi in the Libyan city of Misrata in April.

The group hailed the impact of the convention however, saying that member states had destroyed a nearly 600,000 cluster munitions containing more than 64.5 submunitions.