KABUL // Sher Alim was so enraged by the US soldiers patrolling his village that he considered picking up his gun and firing at them.
But Mr Alim, 36, is no Taliban fighter. A member of the Afghan Local Police (ALP) in Afghanistan's Wardak province, he is armed, trained and mentored by US Special Forces to battle insurgents.
"We were on a joint patrol and it was time for afternoon prayers," Mr Alim said. "But the Americans said we couldn't stop to pray. Why should I obey the infidel's command rather than God's? I wanted to fight them."
Mr Alim's dispute with his US mentors was eventually resolved without bloodshed, but lately not all quarrels between Afghan army and police and their foreign counterparts have ended peacefully.
Recently, uniformed Afghan recruits, many of whom have no links to the Taliban-led insurgency, have been killing more Nato soldiers.
Of the seven attacks by uniformed Afghan army or police against foreign troops this year, which killed 18 people, at least three were personal disputes between Afghan and coalition soldiers, Nato says. The other four were attributed to Taliban insurgents who had infiltrated the security services.
Last month, a 20-year veteran of the Afghan air force shot dead eight US soldiers and another US civilian contractor at the Kabul airport after a heated argument with a US military officer.
Lt Col David Simons, a spokesman for the Nato police and army training mission in Afghanistan, said: "I'd liken these types of incidents to a bar fight in the United States. The only difference is, here they have guns, and defending your honour is a whole lot more important than getting your butt kicked at a bar."
Nato is undertaking a mammoth mission to train and equip the Afghan national army and police before a drawdown of foreign troops begins in July, and security is handed over completely to Afghan forces in 2014. The coalition is spending US$11.6 billion (Dh42.6bn) in 2011 to vet, train and equip Afghan security forces, sending hundreds of foreign military personnel to mentor new recruits at Nato and Afghan bases.
Nato hopes to recruit and train an additional 300,000 Afghan army and police by the end of this year. Right now, the Afghan army has about 149,000 soldiers, while the police force has roughly 134,000 uniformed officers.
But in the race to bolster the ranks before a pull-out, vetting procedures are often lax, and Taliban insurgents, drug-users and the mentally ill are allowed to join.
A Nato official, speaking on the condition of anonymity, said the medical screening of Afghan recruits is not extensive enough to include full-scale psychological evaluations.
Violence has hit its highest levels since the war began in 2001, with Afghan national army and police bearing the brunt of Taliban-led attacks.
Azizuddin Hemat, the head of the Afghan Psychological Union, which is made up of mental-health professionals, said: "I've worked with many former police and soldiers in the hospitals and many of them are depressed, suffering from stress and using drugs. Anything can set them off, especially if they feel they are being disrespected by a foreign soldier".
In addition, a growing number of Afghans, including members of the army and police, are fed up with the 10-year international presence here. Soldiers and police recruits describe scenes where under the stress of combat, particularly in the country's volatile provinces, Afghan pride clashes with US military bravado.
"We are as different as the earth and the sky," the spokesman for the police chief in Baghlan province, Jawad Basharat, said of his foreign counterparts. "When foreign forces don't pay attention to the rules of Afghan or Islamic society, of course there will be problems."
The assistant spokesman for the Afghan Ministry of Defence, Dawlat Waziri, says the ministry runs a special directorate that dispatches religious scholars and cultural advisers to counsel Afghan soldiers on how to tolerate and understand the behaviour of foreign troops. Nato runs similar training programmes on Afghan culture for its soldiers.
"I tell them: 'Those people who are here to help you, and help rebuild your country, you should welcome them'," Mr Waziri says. "We are a hospitable nation."
Still, Nato forces are wary and Lt Colonel Simons said that since last month's deadly shooting at Kabul airport, "the [Nato] force protection apparatus has greatly changed".
Mr Alim, from Wardak, said he had given Nato forces his own set of demands, refusing to work as a local police officer if he is unable to pray while on patrol.
"We gave them these conditions, and we will see if they accept," Mr Alim said. "But if they say no, there is no one to fight for but God."