The U.S. government’s Special Inspector General for Afghanistan Reconstruction (SEGAR) report released Wednesday said that widespread corruption in Afghanistan has undermined efforts to rebuild the country and urged the U.S. mission to make anticorruption efforts a top priority.

The US report said corruption fueled grievances against the Afghan government and channeled material support to the insurgency.

The report, entitled: “Corruption in Conflict: Lessons from the U.S. Experience in Afghanistan,” suggests the U.S. government should have viewed anticorruption as an essential part of its goals after the 2001 U.S.-led invasion that toppled the Taliban regime in Afghanistan.

SIGAR’s report quoted Ryan Crocker, who re-opened the U.S. Embassy in Kabul soon after the Sept. 11, 2001 attacks and served again as ambassador in 2011-2012 as saying that “the ultimate point of failure for our efforts . wasn’t an insurgency. It was the weight of endemic corruption.”

“The corruption lens has got to be in place at the outset, and even before the outset, in the formulation of reconstruction and development strategy, because once it gets to the level I saw . it’s somewhere between unbelievably hard and outright impossible to fix,” Crocker added.

The report further noted that U.S. policies and practices were partly to blame for the growth of corruption. In 2009 and 2010, the emerging concern was that poor U.S. oversight, procurement, and contracting practices were enabling corrupt behavior, it said. Without sufficient controls on U.S. funds, millions of dollars in U.S. reconstruction funds for Afghanistan were being wasted.

“In Afghanistan today, corruption remains an enormous challenge to security, political stability, and development,” SIGAR said.

Meanwhile, Political critics of the government have also considered the Afghan politicians have failed in fight against corruption.

According to them, employing corrupt figures in the regime is causing more corruption.

While the Presidential Palace called the corruption a heritage from the previous government, it emphasizes that the leaders of National Unity Government have serious will in fighting against corruption.

More than $100bn in aid after 2001 helped enrich patronage networks and powerbrokers, discrediting international donors in the eyes of the Afghan population. And whenever the US did attempt to improve accountability, the Afghan government resisted, the report says.

As a result, corruption – which had permeated Afghan public life for centuries – swelled to unprecedented levels.

Sigar partly blames the Afghan government, though it has lived up to some commitments to donors, such as forming an independent anti-corruption committee. The committee, however, receives “uneven political support”, Sigar says, and has no legal authority.

Sigar’s conclusions cohere with the view of analysts in Kabul. There is a direct link between US funds feeding corruption and the erosion of security, said Toofan Waziri, a security analyst.

The lack of results in eradicating corruption has disappointed supporters of President Ashraf Ghani, a former World Bank technocrat who campaigned on pledges to do just that. Since he took power in September 2014, Ghani has failed to recover almost $1bn stolen in a giant fraud at Kabul Bank.