WASHINGTON- The combined budget for U.S. civilian and military intelligence operations has shrunk by more than 15 percent since 2010, official figures show.

The total U.S. intelligence budget was $67.9 billion in the fiscal year to Sept. 30, according to official figures. That was up only marginally from $67.6 billion the previous year, but followed a steady decline since a peak in 2010.

The decline reflected the end of military operations in Iraq in 2011 and the drawdown in Afghanistan, said Bruce Riedel, a former senior intelligence official and security adviser to President Barack Obama.

"Those operations were extremely expensive, not just for the military but also all the civilian agencies. Now that military operations have resumed in Iraq and spread to Syria the costs for intelligence will go back up again," he said.

Steven Aftergood, an intelligence expert with the Federation of American Scientists, also linked the cutbacks partly with the end of engagements in Iraq and Afghanistan.

The overall 2013-2014 budget included $50.5 billion for "National Intelligence Program" activities, which include such agencies as the CIA, and another $17.4 for military intelligence activities, officials said.

Figures laying the long-term trend were compiled by the Federation of American Scientists and validated by an intelligence official.