DERA ISMAIL KHAN, Pakistan – Suspected American drones fired several missiles into three militant hideouts near the Afghan border on Sunday, killing nine Pakistani Taliban fighters, intelligence officials said.

The strikes targeted the group’s hideouts in the South Waziristan tribal region, the three officials said, speaking on condition of anonymity because they were not authorized to talk to the media. The identity of the killed militants was not immediately known, they said, but two important commanders of the Pakistani Taliban – including the head of a training unit for suicide bombers – may be among them.

Sunday’s drone attack was the third suspected U.S. drone strike in five days. One such hit late Wednesday night killed a top Pakistani militant commander, Maulvi Nazir, accused of carrying out deadly attacks against American and other targets across the border in Afghanistan. That attack was followed close on by another strike on Thursday in the North Waziristan tribal area.

Islamabad opposes the use of U.S. drones on its territory, but is believed to have tacitly approved some strikes in the past. The drone campaign also infuriates many Pakistanis who see them as a violation of their country’s sovereignty. Many Pakistanis complain that innocent civilians have also been killed, something the U.S. rejects.

But an attack such as Sunday’s may be less likely to anger the Pakistani military and public because it targeted militants believed to have been going after targets in Pakistan and not in neighboring Afghanistan.

The Pakistani intelligence officials said that informants had told them one of the two dead commanders was Wali Muhammad Mahsud, also known as Toofan, who headed a wing of the group that trained suicide bombers. His predecessor, Qari Husain Mehsud, was believed to have been killed in a U.S. missile strike in late 2011.