The defense department says Pakistan is refusing to participate in the US investigation of last week's Nato bombing along the Afghanistan border that killed 24 Pakistani soldiers.
Defense department spokesman George Little says the US has asked Pakistan to be part of the investigation, but that the Pakistanis have "elected to date" to not participate.
Little refers to the bombing as a "bump in the road" for US-Pakistani counterterrorism cooperation.
Another Pentagon spokesman, Navy Capt. John Kirby, says it's too early to assign blame for the deaths because the investigation is not yet complete.