RAE-EDZO, Northwest Territories (AP) - Two native groups in the Arctic will become the largest non-government landholders in North America under a historic agreement signed by Prime Minister Brian Mulroney.

The long-delayed agreement, signed in this tiny community 200 miles south of the Arctic Circle on the shores of Great Slave Lake, will give the Denes and Metis Indian nations nearly 4,000 square miles of land and special rights to an area the size of Oklahoma.Mulroney said the signing marked a "day of justice" and heralds "new economic and political development" for the north. But native leaders say many specifics must be negotiated before a final pact is signed in two years.

Monday's agreement gives about 15,000 natives of the Dene and Metis Indian nations ownership and oil and mineral rights to about 3,850 square miles of the rocky bush land bordering the Arctic Ocean.

It would also give them special rights and interests - including a voice in wildlife, forestry and land management - for a nearly 70,000 square mile area.

The agreement, which followed 15 years of negotiations, includes a $405 million cash settlement that would be paid out over 20 years beginning in 1990 - the year negotiators hope to have a final settlement.

"This agreement of principle, when carried forward to its final form, will establish a new, stronger and healthier relationship between the people of this area and the governments which serve them," said Mulroney.