U.S. Interior Secretary Gale Norton is stepping down after five years overseeing the nation's federal lands and nature reserves.

The nation's first female interior secretary, Norton said in her resignation letter to President Bush that she will leave her job at the end of the month. Mr. Bush appointed her to the position at the start of his first term in office.

Norton has often clashed with environmentalists over energy production and use of federal land. She helped open up more federal lands to logging and backed an unsuccessful effort to open an Alaskan wildlife refuge to oil drilling.

A statement from the Department of the Interior says Norton accomplished the dual goal of conserving natural resources while helping to increase the nation's energy production.

Some information for this report provided by AP and Reuters.