The United States is preparing to execute a member of its own military for the first time in nearly half-a-century.

U.S. President George Bush approved the execution of U.S. Army private Ronald Gray late Monday.

White House spokeswoman Dana Perino said it was a "serious and difficult decision," but that the facts of the case left no doubt that the death sentence was justified.

A military court convicted Gray in 1988 of two murders, one attempted murder and three rapes, all committed while he served at Fort Bragg, North Carolina in the eastern U.S.  He has been held in a military prison in the midwestern state of Kansas since 1988.

The U.S. military justice system requires the president to approve an execution before it can be carried out.

Gray is expected to appeal the decision.

There are six men currently on the U.S. military's death row.

The last U.S. president to approve a military execution was Dwight Eisenhower.

He approved the death penalty for an Army private convicted of raping a child in 1957.  The U.S. did not execute the soldier until 1961.

In 1962, President John F. Kennedy commuted a death sentence to life in prison.