The Pentagon may have hit a speed bump in the expansion of its growing worldwide information operations.

The Senate Armed Services Committee has asked Defense Secretary Leon Panetta to assess the effectiveness of a series of news and information Web sites that have been initiated by U.S. Special Operations Command (SOCOM) in recent years in a bid to counter extremist messaging. The so-called “influence Web sites” are maintained by various overseas commands and operated by defense contractors.

For fiscal 2012, SOCOM sought $22.6 million in the Overseas Contingency Operations account — primarily intended to fund the wars in Afghanistan and Iraq — for the initiative.

Congress, over the past few years, has been pressing the Pentagon to justify the hundreds of millions of dollars spent overseas under various headings such as “strategic communications” and “information operations.”

In the latest challenge, the Senate Armed Services Committee noted in a legislative report that information ops Web sites “have become a significant and costly component” of U.S. military commands’ campaigns to counter violent extremism, “despite there being limited information to demonstrate ... [they] are reaching or appropriately influencing their intended target audience in support of U.S. national security objectives.”

Among the Web sites are Magharebia, which covers North Africa and is operated under U.S. Africa Command; Central Asia Online, under U.S. Central Command, which covers countries such as Uzbekistan, Kyrgyzstan, and Kazakhstan; and the Southeast European Times, under U.S. European Command, which covers the Balkans, Greece and Turkey.

While the committee said it supports the objectives of the program, it wants more specifics — including a determination on whether the sites are reaching audiences in areas where Internet access is “readily available” and where “U.S. national security interests are of immediate concern.”

For now, the panel recommended cutting the funds by 50 percent, to $11.3 million, and then holding that amount until Panetta certifies the effectiveness of the program. The recommendation was made as part of the fiscal 2012 defense authorization legislation, which was recently passed by the Senate but that may draw a veto from the administration.