Citing a number of recent incidents by the Sri Lankan government's opposition to the ongoing investigation by the United Nations Office of the High Commissioner for Human Rights into human rights violations in Sri Lanka, they said the rights defenders in the country face widespread intimidation.
The letter was jointly drafted by International committee of Jurists, Amnesty International, Asia Forum for Human Rights and Development, CIVICUS, the International Movement Against Discrimination and All Forms of Racism, and the International Service for Human Rights wrote a letter in this regard to the president Of UNHRC and Sri Lankan government.
It makes specific calls for action to the government of Sri Lanka, to the President of the Human Rights Council, and to the member states of the Council.
The government spokesman and media minister, Keheliya Rambukwella, has reportedly threatened all those who intend to provide information to the UN investigation and promised to "take appropriate action based on the evidence the detractors give".
"We stress that threats, harassment, intimidation and reprisals against persons who engage with the UN are prohibited by international human rights law," the letter said.
"While we affirm the importance of exercising the right to free expression by journalists and others, we stress that the exercise of speech that serves to significantly risk inciting violence, hostility or discrimination against persons is unacceptable," it added.
"As a state party to the International Covenant on Civil and Political Rights, Sri Lanka is legally obliged to protect human rights defenders from harassment, reprisals and other attacks," the letter said.
Sri Lanka had vowed not to cooperate with the UN probe saying it infringed on the country's sovereignty.
Sri Lanka has rejected a UNHRC resolution in March that called for an international investigation into allegations that 40,000 civilians were killed in the final months of the civil war that ended in 2009.

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