Karzai blames foreign spies for Afghan troops' attacks on U.S. soldiers

“The investigation done so far shows there is infiltration by foreign spy agencies,” Mr. Faizi said. “There is no doubt there is infiltration.”

NATO’s recent assessment, however, was that only about 1 in 10 of the insider killings were directly linked to infiltration, which it describes as Taliban insurgents who pose as soldiers or police officers, or active Afghan service members who have been won over to the Taliban cause. Roughly 90 percent of the attacks were concluded to have stemmed from personal disputes, stress or cultural clashes.

Many Western officials here, and American officials at the Pentagon, were surprised by the government’s assertions, and some privately sought to discount the spokesman’s remarks.

“We don’t have indications that foreign entities are the locus of sponsorship for insider-attack threats,” said a senior Pentagon official, who spoke on condition of anonymity to avoid publicly differing with the Afghan president.