The U.S. has launched a second round of airstrikes against a target of the Islamic State of Iraq and the Levant (ISIS or ISIL), the Pentagon said Friday afternoon, killing “terrorists” who had launched attacks from mortars.

Pentagon spokesman Rear Adm. John Kirby said the U.S. conducted two additional airstrikes Friday to attack ISIS targets near the Kurdish capital of Erbil, where about 150 U.S. military advisers and other personnel are located. After an initial strike at 6:45 a.m. ET, a remotely piloted aircraft struck a mortar position a bit more than three hours later, around 10 a.m. ET.

“When ISIL fighters returned to the site moments later, the terrorists were attacked again and successfully eliminated,” Kirby said.

Then, at approximately 11:20 a.m. ET, four F/A-18 fighter jets successfully struck a stationary ISIL convoy of seven vehicles and a mortar position near the city of Erbil. Each aircraft executed two passes, dropping one laser-guided bomb each time. In total, eight bombs were dropped in the strike. The Pentagon said the insurgents were “neutralized.”

Kirby had previously announced the initial strike against ISIS artillery early Friday morning. In that strike, two F/A 18 fighter aircraft dropped 500-pound laser-guided bombs on a mobile artillery piece near the Kurdish capital of Erbil. The decision to strike was made by the U.S. Central Command commander in Iraq under the authorization granted by President Barack Obama.

“As the president made clear, the United States military will continue to take direct action against ISIL when they threaten our personnel and facilities,” Kirby said.

Obama said in a statement from the White House on Thursday night that he authorised targeted airstrikes to protect U.S. personnel if militants move on the town of Erbil or the U.S. Embassy in Baghdad, where Americans are currently stationed. He also directed the U.S. military to provide humanitarian aid to Iraqis who are part of the Yazidi religious sect and other religious minorities.

White House press secretary Josh Earnest said Friday that while there was no “specific end date” for U.S. airstrikes, a “prolonged military conflict that includes U.S. involvement is not on the table.”

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