Islamabad ? The U.S. and Pakistan are almost certain a U.S. missile strike killed the head of Pakistan’s Taliban and that his death led to a fierce power struggle among his deputies, officials said Sunday, despite claims and counterclaims as to the fate of the country’s most wanted man.

Government and intelligence officials, as well as some Taliban commanders and at least one rival militant, have said Baitullah Mehsud likely died in Wednesday’s drone strike on his father-in-law’s house in northwestern Pakistan’s rugged, lawless tribal area near the Afghan border.

President Barack Obama’s national security adviser, James Jones, said the U.S. was 90 percent confident Mehsud had been killed. But three Taliban commanders — Hakimullah, Qari Hussain, who is known for training suicide bombers, and Taliban spokesman Maulvi Umar — called AP reporters Saturday insisting Mehsud was alive.

Neither side has produced any concrete evidence, and the claims were impossible to verify.