According to US Defence Department statistics, there have been more US casualties in almost seven months than were killed in Vietnam from 1962-64.
An analysis of the statistics shows that the Vietnam War produced 392 fatal casualties from 1962-64, when American troop levels stood at around 17,000.
By comparison, 397 Americans have died since the US launched its invasion of Iraq in April.
There are 130,000 US troops currently in Iraq - the same number reached in Vietnam by October 1965.
The casualty count for Iraq apparently surpassed the Vietnam figure last Sunday, when a US soldier killed in a rocket-propelled grenade attack became the conflict's 393rd American casualty.
Larger still is the number of American casualties from the broader US "war on terrorism", which has produced 488 military deaths in Iraq, Afghanistan, the Philippines, Southwest Asia and other locations.
Vietnam 1962-64: 392
Iraq 2003: 397
War on Terror: 91
US defence department
Statistics from battle zones outside Iraq show that 91 soldiers have died since 7 October, 2001, as part of Operation Enduring Freedom.
US President George Bush launched the offensive by first attacking Afghanistan's former Taliban regime in November 2001.
However, the Bush administration has rejected comparisons between Iraq and Vietnam, which traumatised Americans with a procession of body bags and television footage of grim wartime cruelty.
More than 58,000 US military personnel died in Vietnam before the war ended in the mid-1970s.
Recent opinion polls show public support for the president eroding as he heads toward the 2004 election, partly because of public concern over the deadly cycle of guerrilla attacks and bombings in Iraq.