The United States says its forces have launched a second wave of air strikes against Islamic State (IS) in northern Iraq.
The Pentagon said on August 8 that U.S. drones destroyed a mortar position and killed a group of militants on August 8.
Spokesman Rear Admiral John Kirby said U.S. Navy fighter jets later used laser-guided bombs to hit a convoy of seven IS vehicles.
The attacks took place near the city of Irbil - a similar location to a first strike earlier in the day.
The Pentagon said two warplanes dropped laser-guided bombs on a mobile artillery piece in that air strike.
It said the Islamist militants had been using the artillery to shell Kurdish forces defending Irbil where U.S. personnel are located.
The United States also announced a second air drop of supplies to the members of the Yazidi sect, thousands of which have been encircled by militants in the northern Sinjar area.
Kirby said the supplies included more than 28,000 U.S. military rations and some 5,500 liters of drinking water.
Meanwhile, the White House said Vice-President Joe Biden called Iraqi President Fuad Masum on August 8 and reiterated President Obama's commitment to “support Iraq and all of its citizens.”
President Barack Obama on August 7 authorized air strikes on Iraq to protect U.S. military and diplomatic personnel in Irbil and prevent "a potential act of genocide" against religious minorities.
White House spokesman Josh Earnest said on August 8 that until Iraq forms a new inclusive government, the United States will focus on military strikes to protect American personnel and address the humanitarian situation at Mount Sinjar.
Earnest said any future additional support to Iraq would not be prolonged and would not involve ground troops.
After seizing Iraq's second-largest city Mosul in June, the Islamic State, then known as the Islamic State in Iraq and the Levant, advanced across the north, pushing back Kurdish forces and coming within 60 kilometers of Irbil.
Tens of thousands of Yazidis and Christians have fled their homes ahead of advancing IS forces.
Iraq's Human Rights Ministry said on August 8 that the militants have taken captive hundreds of Yazidi women.
AP news agency quoted ministry spokesman Kamil Amin as saying some were being held in schools in Iraq's northern city of Mosul.
On August 7, the group said it had seized 17 Iraqi cities, towns and targets -- including a dam and a military base -- over the previous five days, including Qaraqoush, the largest Christian town in Iraq.
Reports say there are an estimated 3,000 Christian refugees in Irbil.
U.S. Secretary of State John Kerry said on August 8 that Iraq was facing "a gut-wrenching humanitarian crisis."
In a first reaction to the August 8 U.S. air strikes, Iraq's army chief of staff said he expects federal troops and Kurdish Peshmerga forces to reclaim large swaths of land after the U.S. air strikes on Islamist positions.
Lieutenant General Babaker Zebari said, "There will be huge changes on the ground in the coming hours."
Reuters news agency quoted an unidentified U.S. official as saying the Iraqi government delivered a plane load of ammunition to Irbil on August 8, in an unprecedented act of military cooperation between Kurdish and Iraqi forces.
Prime Minister Nuri al-Maliki previously ordered the Iraqi air force to support peshmerga fighters in their fight against IS.