BILLINGS, Mont. -- Nez Perce tribal leaders say they intend to sharply expand their bison hunt outside of Yellowstone Park this winter, harvesting up to 70 animals.

The hunt is allowed under an 1855 treaty between the Lapwai, Idaho-based tribe and the federal government.

Only six bison were taken last year during a limited "youth hunt."

The hunt now is being opened to all Nez Perce members. This year's hunt began last weekend and four bison have been taken so far.

The Nez Perce Tribe Fish and Wildlife Commission has also issued five permits for elk.

Nez Perce Chairman Rebecca Miles sent a letter to Montana officials earlier this month, saying moose, bighorn sheep, mountain goats and antelope might also be taken.

But commission member Joseph Oatman says the harvest of those species is on hold until the tribe can talk with Montana wildlife officials about how many of those animals can be killed without impacting the species' populations. He said it is possible none will be taken this year.

The state of Montana has issued 140 permits to Montana hunters this year.