Story highlights

Attacks by Afghan security forces on U.S. troops have been rising

They add to mistrust as Americans try to train their Afghan counterparts

France has suspended its mission because of attacks on French soldiers

The congressional hearing was prompted by an attack last year

Washington CNN —  

A congressional panel Wednesday took up the uneasy topic of Afghan security forces turning on their international allies, incidents that have fueled mutual distrust at a critical juncture of the long-running conflict.

Rep. Buck McKeon, the California Republican who chairs the Armed Services Committee, said existing security procedures failed to identify 42 attackers between 2007 and 2011, all members of the Afghan National Security Force. Three other attacks were perpetrated by contracted employees.

“This is 42 attacks too many, and the new process must do better,” McKeon said.

That number did not include the latest incident, in which a man wearing an Afghan National Army uniform killed a coalition forces member in southern Afghanistan on Tuesday.

The panel heard testimony from four defense officials who laid out delicate issues pertaining to Afghan security forces, among them the vetting of Afghans brought onto coalition bases to provide security.

The defense officials said that in 58% of cases, the attackers were not puppets of insurgent groups but acted on their own accord, perhaps over a personal dispute.

Such disputes can arise from cultural misunderstanding, religious and ideological friction or combat stress, said Brig. Gen. Stephen Townsend, director of the Pakistan/Afghanistan Coordination Cell in the Joint Chiefs of Staff office.

He said cultural training has been vital for U.S. soldiers, and now the Afghans are considering doing the same in providing better understanding of Americans.

Another chunk of perpetrators involved insurgents who were able to pass themselves off as Afghan soldiers and infiltrate bases.

David Sedney, deputy assistant secretary of state for the region, said the greater the partnership between Afghans and coalition troops on providing security, the greater the risks are to Americans. At issue was also the problem of Afghan soldiers turning on one another and on civilian populations.

“No system is perfect … but no system is static,” Sedney said.

The hearing was prompted by an attack that occurred at Forward Operating Base Frontenac in March.

In that Kandahar province incident, an Afghan man hired by private security contractor Tundra killed two soldiers and wounded four others. One was Spc. Rudy Acosta, who was from McKeon’s district and whose parents attended Wednesday’s hearing

McKeon read out a statement from Acosta’s father, Dante Acosta, who received an Army report last month on the Frontenac investigation.

“The report highlighted the fact that although the U.S. government allows private security contractors to provide base security in hostile lands, basic levels of safeguards were either not implemented or not followed,” the statement said. “This allowed an Afghan national who made prior threats against U.S. troops to be re-employed by Tundra Security and carry out a lethal attack.”

Acosta told CNN that other fathers should never have to feel his anguish. Afghans, he believes, should not be the ones protecting American bases.

“When we don’t do our level best to ensure the basic security of our service men and women, I think we’re failing them in a huge way,” he said. “We have to make sure that as of right now, the call goes out, the orders go out, ‘Hey, this is the way it’s going to be done. We’re going to do this securely and safely and here’s why.’”

The NATO-led coalition is attempting to stand up local forces to take over security in war-ravaged Afghanistan as foreign troop levels fall.

President Barack Obama has announced a U.S. withdrawal in 2014. France suspended its operations after four French soldiers were killed by Afghan counterparts in eastern Kapisa province in January.

In December, another Afghan soldier killed two French soldiers serving in an engineers’ regiment.

“The French army is not in Afghanistan to be shot at by Afghan soldiers,” French President Nicolas Sarkozy said after the January shooting.

Last year, Afghan air force officer Ahmed Gul killed eight American airmen and a security contractor.

Gul had declared his desire to kill Americans, behaved erratically at work and frequented a mosque known for its anti-American views, according to a U.S. Air Force investigation into the incident.

A NATO analysis last year found that 52 U.S. and allied soldiers had been killed in “green on blue” attacks between 2005 and June 2011.

The incidents represent a fraction of the total coalition deaths in the war but are are extremely damaging in Afghanistan’s transition.

CNN’s Larry Shaughnessy and Moni Basu contributed to this report.