l for human rights in Cambodia, told reporters that the United Nations was taking steps to establish a tribunal to investigate the crimes of Pol Pot and his colleagues. "It`s very important that the others are brought to trial. Those responsible must be held accountable," Hammarberg told reporters shortly after he arrived in Cambodia on a scheduled visit. Pol Pot died of a heart attack in a Khmer Rouge-controlled village in northern Cambodian near the Thai border late on Wednesday. He was 73. About 1.7 million Cambodians died of starvation or hard labour, or were executed, during his 1975-79 rule. The Khmer Rouge is now led by military chief Ta Mok, who toppled Pol Pot in an internal power struggle last year. Other leaders holed up with Ta Mok in the mountains of northern Cambodia include Khieu Samphan, who defined the Khmer Rouge`s ideology, and Nuon Chea, Pol Pot`s shadowy right-hand man. The Cambodian government said on Friday it still wanted to see Ta Mok, Khieu Samphan and Nuon Chea face trial. Hammarberg said the U.N. human rights commission was taking steps to set up a tribunal for Cambodia. The United Nations, in deference to political sensitivities, had not referred to Pol Pot`s crimes as genocide until last November. The Khmer Rouge were forced from power by a Vietnamese invasion in early 1979. But with the support of Vietnam`s then enemies, China and Thailand, the Khmer Rouge fought a guerrilla war against occupying Vietnamese forces and the Hanoi-backed government in Phnom Penh through the 1980s and early 1990s.