A U.S. drone attack killed at least 15 people on Sunday in Pakistan's South Waziristan region on the Afghan border, Pakistani security officials said.
"Now the death toll is 15. It could rise further. People are still busy removing rubble," a senior security official told Reuters.
Pakistani Taliban issued an audio tape on Saturday purportedly from Mehsud, denying he had been killed in a U.S. missile strike two days earlier.
The latest drone attacks came after Pakistani Foreign Minister Shah Mehmood Qureshi warned the United States that intensified drone attacks or ground operations against in Pakistan could undermine the relations.
Sunday's attack was the tenth missile strike by an unmanned US spy plane so far this year as Pakistan sees a surge in the strikes, which fuel anti-American sentiment in the Muslim nation and draw public condemnation from the government.