"I've got responsibilities in making certain...that we are not used as a tool to be exploited by other countries."

ISLAMABAD, Pakistan — An airstrike believed to have been carried out by a United States drone killed at least 60 people at a funeral for a Taliban fighter in South Waziristan on Tuesday, residents of the area and local news reports said...

The United States carried out 22 previous drone strikes this year, as the Obama administration has intensified a policy inherited from the Bush administration.

Before the attack on Tuesday, the Pakistani Army and Air Force had begun operations in South Waziristan against the forces of the Pakistani Taliban leader, Baitullah Mehsud. The group’s suicide bombings in major cities have terrorized Pakistanis for years.

In a serious blow to Pakistan’s effort, on Tuesday an assassin loyal to Mr. Mehsud shot and killed a rival tribal leader, Qari Zainuddin, whom the government had hoped to use as an ally in its campaign to corner the Taliban leader.