An Afghan teenager who lost both legs in a cluster bomb explosion helped persuade his country to change its stance and join nearly 100 nations in signing a treaty Wednesday banning the disputed weapons. Afghanistan was initially reluctant to join the pact _ which the United States and Russia have refused to support _ but agreed to after lobbying by victims maimed by cluster munitions, including 17-year-old Soraj Ghulan Habib. The teen, who uses a wheelchair, met with his country's ambassador to Norway, Jawed Ludin, at a two-day signing conference in Oslo. “I explained to the ambassador my situation, and that the people of Afghanistan wanted a ban,” Habib, who said he was crippled by a cluster bomb seven years ago, told The Associated Press. Speaking through an interpreter, Habib said the ambassador called Afghan President Hamid Karzai, who agreed to change his stance on the treaty. “Today is a historic day,” Habib declared. Afghanistan's reversal even surprised the activists who are urging countries to join the pact against cluster munitions, which have been widely criticized for maiming and killing civilians. “It is just so huge, to get this turnaround. Afghanistan was under a lot of pressure from the United States,” said Thomas Nash, coordinator of The Cluster Bomb Coalition. “If Afghanistan can withstand the pressure, so can others.” Australian activist Daniel Barty said the Afghan ambassador appeared to start changing his mind after meeting Habib at a reception Tuesday. The US, Russia and other countries refusing to sign the treaty say cluster bombs have legitimate military uses, such as repelling advancing troop columns. The group Handicap International says 98 percent of cluster-bomb victims are civilians, and 27 percent are children. Organizers hoped that more than 100 of the 125 countries represented will have signed by the end of the conference on Thursday. Norwegian Foreign Minister Jonas Gahr Stoere said 92 countries did so on Wednesday. The treaty must be ratified by 30 countries before it takes effect.