Delegates from more than 120 countries opened negotiations Monday on an international convention that would ban the use, production, trade and storage of cluster bombs that cause unacceptable harm to civilians, AP reported. Talks on the convention, first launched by Austria, Ireland, Mexico, New Zealand, Norway, Peru and the Vatican last year, aim to define which cluster bomb weapons should be banned and which, such as those dispensing chaff used to deflect airborne missiles, can continue to be used. «What we're trying to prohibit is those cluster munitions that cause unacceptable harm to civilians,» the conference chairman, New Zealand Disarmament Ambassador Don Mackay. Some 41 of the 76 states in the world that stockpile cluster munitions are taking part in the negotiations, along with a majority of the weapon producers. However, major producers such as the U.S., Russia, China and Pakistan have not joined the process and have no observers at this week's conference in the New Zealand capital, Wellington. Cluster bombs are built to explode above the ground, releasing thousands of bomblets primed to detonate on impact. But combat results show between 10 percent and 40 percent fail to go off and lie primed in the target area to kill and injure civilians. Talks on the convention were launched in Oslo, Norway last year, and this week's negotiations are the last talks among senior officials before final diplomatic negotiations scheduled for May in Ireland.