However, a senior U.S. defense official said that doesn't appear to be the case, The Wall Street Journal reported.
Aimal Faizi, a spokesman for Afghan President Hamid Karzai, told reporters foreign spy agencies from countries in the region are growing "fearful of the empowerment of Afghan security agencies."
"The hands behind these events are the foreign spy agencies using the Taliban," the Journal quoted Faizi as telling reporters.
Faizi didn't name any countries or provide proof of their involvement, but the Journal noted the Afghan government has often charged Iran and Pakistan with backing the insurgency. Those two countries have denied the accusations.
A senior U.S. defense official whose name was not reported suggested the Afghan government should look inward for the source of the attacks.
"It's our understanding that these attacks aren't the work of foreign intelligence services," the official said. "They're typically Afghans who themselves decide to conduct them, and some Afghans might have help on occasion from insurgent networks."
Notable deaths of 2014 [PHOTOS]