The United Nations High Commissioner for Human Rights Louise Arbour said in a statement that Monday's announcement of an internationally-supervised investigation into gross abuses was welcome.
"Any commission of inquiry can only investigate a selection of cases, and that a broader international mechanism is still needed to monitor, ultimately prevent, human rights violations in the longer term," she said.
Sri Lanka on Monday said it will probe charges that troops and Tamil Tiger rebels had killed hundreds of civilians since August last year.
Among the high-profile cases to be immediately probed are the massacre of 17 aid workers employed by a French charity, the killing of 68 bus passengers and the slaying of foreign minister Lakshman Kadirgamar last year.
President Mahinda Rajapakse set up the commission which will be supervised by a panel nominated by Australia, Britain, Canada, the European Union, Japan, Netherlands and the US, Human Rights Minister Mahinda Samarasinghe said.
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