MIR ALI, Pakistan — The Pakistani Taliban claimed today that they used a turncoat CIA operative to carry out a suicide bombing that killed seven American CIA employees in Afghanistan as revenge for a top militant leader's death in U.S. missile strike.

The announcement was nearly impossible to verify independently because it involves covert operations in a dangerous region. It is highly unusual for the Pakistani Taliban to claim credit for an attack in Afghanistan, and the proclamation followed indications the Afghan Taliban may have been involved in the attack.

CIA spokesman George Little could not confirm the account.

"There is much about the attack that isn't yet known, but this much is clear: The CIA's resolve to pursue aggressive counterterrorism operations is greater than ever," he told The Associated Press.

The suicide bomber struck the CIA's operation at Camp Chapman in eastern Khost province on Wednesday.

Six other people were wounded in what was one of the worst attacks in CIA history.