Yemen\'s Nobel Peace Prize winner Tawakkul Karman says the UN must act \"immediately and decisively\" to halt a deadly government crackdown on protesters calling for President Ali Abdullah Saleh to resign.Yemen\'s Nobel Peace Prize winner Tawakkul Karman urged the United Nations \"to take immediate and decisive action to stop the massacres and hold the perpetrators accountable,\" in a letter to UN chief Ban Ki-moon, a copy of which she showed to AFP late Monday during a visit to Doha.\"This is the only thing that will give Yemenis ... belief that international justice exists ... and that it extends far enough to reach Saleh, his gang and all the despots who continue to kill innocents.\"Karman and tens of thousands of other pro-democracy activists have for months been camped out in Sanaa\'s Change Square, marching against Saleh despite a violent crackdown by government troops that has killed hundreds since the mass protest movement began in late January.\"Protect the peaceful protesters in Yemen,\" she wrote in the letter, addressing the Security Council. \"In the name of the victims and in the name of our people, I call on you to take Saleh and his regime to the International Criminal Court.\"The Security Council is currently drafting a resolution calling on all sides to stop the violence and for Saleh to sign a Gulf Cooperation Council initiative and step down.Saleh has for months refused to sign the GCC initiative which calls on him to hand power over to his vice president in return for immunity from prosecution.