US warplanes have bombed positions of self-declared jihadists in northern Iraq, in what the federal and Kurdish governments vowed would allow them to start clawing back areas lost in two months of conflict.
President Barack Obama's order for the first air strikes on Iraq since he put an end to US occupation in 2011 came after fighters from the Islamic State group made massive gains on the ground, seizing a dam and forcing a mass exodus of religious minorities.
The US operation began with air drops of food and water for thousands of people hiding from the group in a barren northern mountain range. Many people who have been cowering in the Sinjar mountains for five days in searing heat and with no supplies are Yazidis, a minority that follows a 4,000-year-old faith.
Late Friday, the Pentagon said that cargo planes escorted by combat jets made a second air drop of food and water to "thousands of Iraqi citizens" threatened by the fighters on Sinjar mountain.
Obama accused the Islamic State group, which calls Yazidis "devil-worshippers", of attempting "the systematic destruction of the entire people, which would constitute genocide".