The UN special rapporteur on the rights of indigenous peoples has called on the United States to mitigate the "sense of loss" among the Native American community by restoring some tribal lands.
James Anaya, made the comments after a 12-day tour of the United States, during which he met with tribal leaders in the capital as well as in the states of Arizona, Alaska, Oklahoma, Oregon, South Dakota and Washington.
"The sense of loss, alienation and indignity is pervasive throughout Indian country," Anaya said in a statement released Friday.
"It is evident that there have still not been adequate measures of reconciliation to overcome the persistent legacies of the history of oppression, and that there is still much healing that needs to be done."
He pointed to the loss of tribal lands as a particularly sore point, naming the Black Hills of South Dakota and the San Francisco Peaks in Arizona as places where indigenous peoples feel they have "too little control."
"Securing the rights of indigenous peoples to their lands is of central importance to indigenous peoples' socio-economic development, self-determination, and cultural integrity," Anaya said.
"Continued efforts to resolve, clarify, and strengthen the protection of indigenous lands, resources, and sacred sites should be made," he said.
"The widespread loss of indigenous peoples' lands and resources is well-documented. The negative effects of this loss are compounded by past and ongoing activities that diminish or threaten the remaining lands and resources upon which indigenous peoples depend."
Anaya went on the tour to see how well the United States is carrying out the United Nations Declaration on the Rights of Indigenous Peoples, which the administration of President Barack Obama endorsed in December 2010.
He noted that while he visited tribal leaders both on reservations and in urban areas, and met with Obama administration officials, he was unable to meet with members of the US Congress.
Anaya is to draft a report to be presented to the UN Human Rights Council, probably in September, and which will be made public.
"More robust measures are needed to address the serious issues affecting Native American, Alaska Native and Hawaiian peoples in the United States -- issues that are rooted in a dark and complex history," he said.
Anaya said such measures should be taken "in consultation and in real partnership with indigenous peoples, with a goal towards strengthening their own self-determination and decision-making over their affairs at all levels."
Last month, the US Justice Department announced that the government had agreed to pay more than $1 billion to 40 Native American tribes to settle lawsuits over federal use of their lands and assets.
The United States is home to some two million Native Americans, who trail national averages in income and health.