A new congressional analysis shows the Iraq war is now costing taxpayers almost $2 billion a week -- nearly twice as much as in the first year of the conflict three years ago and 20 percent more than last year -- as the Pentagon spends more on establishing regional bases. The total cost of military operations at home and abroad since 2001...will top half a trillion dollars. The spike in operating costs -- including a 20 percent increase over last year in Afghanistan, where the mission now costs about $370 million a week -- comes even though troop levels in both countries have remained stable. [A] major factor...is the building of more extensive infrastructure to support troops and equipment in and around Iraq and Afghanistan," according to the report. Based on Defense Department data, the report suggests that the construction of so-called semi-permanent support bases has picked up in recent months, making it increasingly clear that the US military will have a presence in both countries for years to come. The United States maintains it is not building permanent military bases in Iraq or Afghanistan. "You would expect [operating costs] to level off if you have the same level of people," said the report's principal author, Amy Belasco, a national defense specialist at the Congressional Research Service. "It's a bit mysterious." The Pentagon has not provided Congress with a detailed accounting of all the war funds, making it impossible to conduct a full, independent estimate.