WASHINGTON — Protection of sites held sacred by American Indians and Alaska Natives will be bolstered under a memorandum of understanding signed Thursday by four federal agencies and the Advisory Council on Historic Preservation.

The memo signed by the departments of Agriculture, Defense, Energy and Interior also calls for improving tribal access to sites that are on federal land.

“We have a special, shared responsibility to respect and foster American Indian and Alaska Native cultural and religious heritage, and today’s agreement recognizes that important role,” Interior Secretary Ken Salazar said in a statement.

The agencies plan to work during the next five years to raise awareness about sacred sites. That includes developing a website, a training program for federal employees and guidance for managing sacred sites....