The leader of the Islamic State group's branch in Afghanistan and Pakistan was killed in a U.S. drone strike on July 26, a Pentagon spokesman said on Friday after the Afghan ambassador to Pakistan announced the news to Reuters.

The death of Hafiz Saeed Khan is a blow to efforts by the Islamic State — also known as ISIS or Daesh — to expand from its heartlands in Syria and Iraq into Afghanistan and Pakistan, which already are crowded with jihadi movements, including the Taliban and al-Qaida.

It is the second U.S. killing of a prominent militant in the region in months. In May, a U.S. drone killed Afghan Taliban leader Mullah Akhtar Mansour in a strike in Pakistan.