WASHINGTON (Reuters) - The U.S. war in Iraq now costs more per month than the average monthly cost of military operations in Vietnam in the 1960s and 1970s, according to a report issued on Wednesday.

The report, entitled "The Iraq Quagmire" from the Institute for Policy Studies and Foreign Policy in Focus, both liberal, anti-war organizations, put the cost of current operations in Iraq at $5.6 billion per month. This breaks down to almost $186 million a day.

"By comparison, the average cost of U.S. operations in Vietnam over the eight-year war was $5.1 billion per month, adjusting for inflation," it said.

As a proportion of gross domestic product, the Vietnam War was more significant, costing 12 percent of annual GDP, compared to 2 percent for the Iraq War. However, economists said the Iraq war is being financed with deficit spending and may nearly double the projected federal budget deficit over the next 10 years.

The U.S. Congress has approved four spending bills for Iraq so far with funds totaling $204.4 billion and is expected soon to authorize a further $45.3 billion.

"Broken down per person in the United States, the cost so far is $727, making the Iraq War the most expensive military effort in the past 60 years," wrote authors Phyllis Bennis and Erik Leaver.

As public support for the war drops, more politicians, including some Republicans, have begun to compare it to Vietnam.

The latest was Nebraska Republican Sen. Chuck Hagel, who received two Purple Hearts and other military honors for his service in Vietnam. He said earlier this month that the United States was "locked into a bogged-down problem, not dissimilar to where we were in Vietnam."

The total cost of the Vietnam War in current dollars was around $600 billion and there are some experts who believe the Iraq War will eventually surpass that total.

For instance, the Congressional Budget Office estimated this year that if the United States managed to reduce its troop deployment to Iraq and Afghanistan to 50,000 by 2010, the cost over the next decade would be an additional $393 billion, which when added to the dollars already spent would exceed the Vietnam total.

While there are far fewer troops in Iraq than there were in Vietnam at the height of that conflict, the weapons they use are more expensive and they are paid more.

The report also highlighted the human costs of the war: the deaths of an estimated 23,000-27,000 Iraqi civilians and more than 2,000 U.S. military personnel and civilian contractors; the social costs of domestic programs slashed to meet the budget shortfall; the loss of income to reservists and National Guard troops who spend long periods away from their careers and businesses as well as the anticipated costs of treating returning troops for mental health conditions as a result of their service.

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