three countries signed a treaty banning cluster bombs Thursday, as diplomats accepted the wishes of victims who begged them to bar the weapons that kill and main civilians long after the conflicts end. Some of the world's top military powers _ including the U.S., Russia and China _ refused to attend, arguing cluster bombs have legitimate military uses, such as repelling advancing troop columns. “We're of course disappointed by the states that did not show up here in Oslo,” said Steve Goose, the arms director of Human Rights Watch. “They're on the wrong side of history. Some of them are clinging to what is now a widely discredited weapon.” Under the accord, negotiated in May, signatories agreed not to use cluster bombs, to destroy existing stockpiles within eight years, and to fund programs that clear old battlefields of dud bombs. The pact left open the door open for new types of weapons that could pick targets more precisely and contain self-destruct technology, The treaty goes into effect once 30 countries ratify it, a process which began, in essence, on Thursday. However, the talks in Dublin, Ireland, did not involve the biggest makers and users of the weapons: the United States, Russia, China, Israel, India and Pakistan. Washington has dismissed the prospect that the treaty would alter US policy. However, activists hope President-elect Barack Obama will review the current US position on the weapons, noting that 18 of 26 NATO allies, including Britain, France and Germany, had signed the treaty. Cluster bomblets are packed by the hundreds into artillery shells, bombs or missiles, which scatter them over vast areas. Some fail to explode immediately. The unexploded bomblets can then lie dormant for years until they are disturbed, often by children attracted by their small size and bright colors. The group Handicap International says 98 percent of cluster-bomb victims are civilians, and nearly a third of all victims are children.