ISAF: Pakistani Branch Not The Most Dangerous Taliban Faction

The Haqqani network have been called the "Kennedys of the Taliban."

Hours after the death of Pakistani Taliban leader Hakimullah Mehsud, the militant group's counterparts across the border condemned the "cowardly U.S. drone attack."

"If America believes that by martyring mujahedeen they will somehow create a void and reach their selfish aims then they are greatly mistaken," the Afghan Taliban said in a statement.

Officials blame Mehsud's Pakistani Taliban for the deaths of at least 40,000 civilians and 5,000 troops during its decade-long insurgency against the country's government. The Pakistani Taliban have also been known to support their Afghan brothers-in-arms, who are a separate group under the leadership of the elusive Mullah Mohammed Omar.