A man in an Afghan uniform has shot dead three US soldiers in the eastern province of Paktika, officials have said. An argument between the Afghan soldier and his trainers appeared to have led to Saturday’s shooting on an Afghan National Army base in Paktika’s Kher Qot district, according to a statement from the provincial governor’s office. There was no immediate claim of responsibility, but NATO officials have said that most insider attacks stem from personal grudges and cultural misunderstandings rather than Taliban plots. “Three ISAF members were killed when an individual wearing ANSF (Afghan National Security Force) uniform turned his weapon on them and opened fire,” a local official spokesman said. The foreigners returned fire and killed the Afghan soldier, who had no known connection to the insurgency, according to the local governor’s statement. The deaths of the International Security Assistance Force on Saturday in the district of Khair Kot came on the same day that one Italian soldier was killed and three others were wounded when a grenade was thrown into their armoured vehicle. The Italian soldier was killed and three were wounded in Farah city on Saturday morning when an 11-year old child threw a grenade at a NATO convoy in the western province of Farah, a Taliban spokesman said.