"We have 33 treaties with the United States that they have not lived by," said Phyllis Young, co-organiser of the first international conference on indigenous rights in Geneva in 1977.

"They continue to take our land, our water, our children."

"This is according to the laws of the United States, specifically article six of the constitution," added Russell Means, a veteran Native American activist, referrring to the principle that treaties are the supreme law of the land.

"It is also within the laws on treaties passed at the Vienna Convention and put into effect by the US and the rest of the international community in 1980."

"We are legally within our rights to be free and independent."

Lakota territory ecompasses parts of the states of Nebraska, South Dakota, North Dakota, Montana and Wyoming.

"We are no longer citizens of the United States of America and all those who live in the five-state area that encompasses our country are free to join us," said Means.

They will issue their own passports and driving licences, and exempt residents of Lakota country from taxes -- as long as they renounce their US citizenship.

The declaration of independence is the culmination of a movement started 33 years ago.

It was in 1974 when the Lakota made a 'declaration of continuing independence.'

Since then, they have waiting for the right moment to make their move.

"It takes critical mass to combat colonialism and we wanted to make sure that all our ducks were in a row," said Means.

One recent event that may have encouraged the Lakota was September's non-binding declaration by the United Nations on the rights of indigenous peoples.

The declaration came about in spite of opposition from the US, which said it conflicted with its own laws.

"Our people want to live, not just survive or crawl and be mascots," said Young.

"We are not trying to embarrass the United States."

"We are here to continue the struggle for our children and grandchildren."