A specially appointed congressional watchdog agency has found U.S.-funded reconstruction projects in Afghanistan are failing and costing millions of dollars.

Meanwhile, a range of experts say the standards used to judge the projects are unrealistic and may impede progress in the country.

Congress created the Office of the Special Inspector General for Afghanistan Reconstruction in 2008 to provide project oversight, ensure efficiency and prevent waste and fraud.

The U.S. spent $104 billion on relief work in Afghanistan from 2002 to June 2013, and SIGAR's reports suggest a significant amount of that money has been poured into questionable projects.

This month, SIGAR released its latest report, which provided more fodder. For example, inspectors found poor U.S. government oversight led to the "melting" of an Afghan Special Police training center's dry fire range. The facility, which cost nearly $500,000 to build, began to collapse only four months after it was completed. The report found the contractor used defective construction methods and materials and the Defense Department failed to hold the firm responsible.

That echoes other SIGAR reports saying many reconstruction projects have not been completed even after five years. The common thread, the inspector general's office found, is a lack of oversight from the American government.

While experts agree the U.S. has wasted money in Afghanistan, many say SIGAR does not sufficiently take into account the many difficulties of running such aid programs in a post-conflict zone.

"I feel SIGAR is on a little bit of a vendetta," said Michael O'Hanlon, a senior fellow at the Brookings Institution. "There's always going to be some degree of inefficiency and even waste and perhaps even corruption in most projects in Afghanistan and so finding some of that in any given project and declaring complete failure or implying failure is really not news and it's also not really fair."

However, Gene Aloise, SIGAR's deputy inspector general, said the agency's mandate is to conduct oversight like any other auditing agency.

"It isn't being a cheerleader, it isn't talking about all the successes," he said. "It's finding out how the money was spent for the American taxpayer. Was it spent wisely or not? These are, again, excuses that you're hearing from people as to why they basically screwed up on their mission."

The wildly divergent viewpoints on SIGAR's conclusions have their roots in the office's mandate, written by Congress, said Ronald Neumann, former U.S. ambassador to Afghanistan.

SIGAR does not "have a standard that deals with war. They're trying to survey based on peacetime standards," he said. "I think the need for inspection [and oversight] is real. We're a democracy. Congress has to vote the money, but I think it's unreasonable to have an inspection group that is based on unreasonable standards."

Neumann, now president of the American Academy of Diplomacy, said he has returned to Afghanistan several times since retiring from his ambassador post in 2007.

"There's a lot of things going well and SIGAR's reporting kind of just gives the impression that everything is going to hell and in that respect, it's harmful," he said.

O'Hanlon, co-director of Brookings' Center for 21st Century Security and Intelligence, said a certain perspective is required to evaluate the success of U.S. aid programs. In Afghanistan, he said the goal should be to maintain moderate stability, a process that takes time.

Polls consistently show Afghan citizens favor the current democratic political structure to the Taliban despite the slow recovery process, he noted.

"We're just trying to help the country hold together so that a Taliban takeover does not happen and another al-Qaida sanctuary does not develop on Afghan soil, and that may not require that all these projects be 100 percent successful," O'Hanlon said. "There's absolutely no reason why we should categorically say that the project, the effort, the development aid programs are failing and therefore that we should end them."

Sher Jan Ahmadzai, a research associate at the Center for Afghanistan Studies and a former aide to the president of Afghanistan, said SIGAR's expectations are fair because they reflect the high standards the U.S. used when issuing contracts to local agencies. But, he said, the contracts should not have used such high standards, taking into account the abilities of the local contractors.

With many reports including phrases like "poor planning" or "poor oversight" in their titles, SIGAR reports often generate media buzz. Their findings usually point to the U.S. spending millions of taxpayer dollars on unsuccessful projects.

"It's up to the listener to be fairly sophisticated when SIGAR exposes X million dollars of waste or fraud or abuse or just failed projects," said Daniel Markey, a senior fellow at the Council on Foreign Relations. "You probably do have to tote that up against the total dollar figures of literally tens of billions if not hundreds of billions of dollars spent in Afghanistan over a decade and decide just how significant is that in that broader context."

Markey questioned SIGAR's expectations of the acceptable level of waste associated with each project, emphasizing that it's impractical to assume there should be no waste.

Aloise, SIGAR's deputy inspector general, acknowledged the difficulties of working in a conflict zone, but he said because the contracting agencies accepted money they should be subject to proper oversight.

"The trouble is that there was no strategic planning or thinking about how to do this the right way," he said. "They just poured tons of money into that country that could not absorb it."

The problem of oversight will only intensify as U.S. troops leave Afghanistan, said Marvin Weinbaum of the Middle East Institute, who served as an intelligence analyst for Pakistan and Afghanistan in the State Department from 1999 to 2003.

"We can't put in the kind of monitoring apparatuses that we would need to be confident that we have a program that is ... being effective," Weinbaum said.

He said he also fears the reports may result in the scaling back of U.S. aid programs.

"This is not Minneapolis that you're making these expenditures in," Weinbaum said. "It's an environment where this sort of thing is going to be expected. The question is how much can you tolerate and is there any way in which you can minimize this kind of loss."