"The continuing attacks targeting Christians represent the second major outbreak of religious violence in Orissa since December which underlines the pressing need for Indian government to develop preventive strategies," the United States Commission on International Religious Freedom (USCIRF) said.
"Both state and central governments are responsible to protect every person's right to religious freedom, including members of religious minorities, as guaranteed in international human rights instruments," Commission Chair Felice D Gaer said in a statement.
Communal riots broke out in Orissa's Kandhamal district following the killing of VHP leader swami Lamananda Saraswati on August 23 and at least 16 people have died in the violence.
"The Commission condemns the killing of the Hindu outfit leader and the violence that has followed and supports Indian Prime Minister Manmohan Singh's pledge to offer assistance to survivours of the communal riots," it said.
The USCIRF has called on the US State Department to urge Indian government and its Human Rights and Minority Commission to continue their investigations and bring the perpetrators of the violence into account.
"The current conflict shows that the Orissa government has again failed to protect members of religious minorities," said Gaer.
Earlier in December 2007, similar clashes had broken out in the communally sensitive district.