In principle, the term "friendly fire" denotes the accidental maiming or killing of allied troops in an attempt to disable or obliterate enemy forces. Some use the term with irony, as that which is later described as friendly fire may have been a result of extreme carelessness, indifference or even intent to kill supposed traitors or defectors.
In 1993 the Pentagon reported that up to 10% of deaths in USA forces in Vietnam were inflicted by their own forces. According to a 1992 report, the Pentagon estimated 35 of 148 American combat deaths in the Gulf War were the result of allied fire. Unofficial estimates are that more than 50% of the four-day ground war casualties were from friendly fire. In 1994, 20 allied personnel were killed during helicopter surveillance flights over northern Iraq due to a misidentification by fighter planes of the airforce of the USA.
In 1997, the Pentagon revealed that it secretly knew for decades that thousands of American soldiers were killed and maimed by landmines made in the USA, notably during the wars in Korea and Vietnam. A former Marine Corps commandant is quoted in the report saying "We kill more Americans with our own mines that we do anything else." About 64,000 USA servicemen were killed or wounded by mines during the Vietnam war.