U.S. President Barack Obama says he has authorized the military to carry out air strikes in Iraq against Islamic militants, if needed, to protect U.S. military and diplomatic personnel and in the northern city of Irbil.
Obama added -- in reference to tens of thousands of Yazidis trapped by Islamic State militants -- that "we can act carefully and responsibly to prevent a potential act of genocide."
He said he was therefore authorizing "targeted air strikes, if necessary, to help forces in Iraq as they fight to break the siege and protect the civilians trapped there."
Obama said, however, that he would not "allow the United States to be drawn into fighting another war in Iraq."
He said U.S. planes have begun making airdrops of humanitarian aid to the Yazidis, thousands of whom are without food, water, and shelter on Mount Sinjar, which is encircled by Islamic State fighters.
The office of the UN's High Commissioner for Human Rights said it was "deeply alarmed" by the situation of the Yazidi, Christian, and Turkoman communities in northern Iraq and said systematic attacks against civilian populations because of their ethnic background or religion may constitute crimes against humanity.
Tens of thousands of Yazidis and Christians have fled their homes in recent days ahead of advancing Islamic State forces, who have threatened them with death if they did not leave or convert to Sunni Islam.
Three U.S. aircraft -- accompanied by fighter planes -- dropped 72 bundles of aid to the Yazidis early on August 8, including thousands of liters of water and ready-to-eat meals.
There are estimated to be dozens of U.S. military advisers based in Irbil, the capital of Iraq's Kurdistan region and home to some 1.5 million people.
The United States has a consulate office in Irbil and a military operations center that was set up earlier this year to assist the Iraqi military.
Obama held long meetings with his national security team on August 7 to discuss the situation in Iraq.
In New York, the UN Security Council issued a statement condemning attacks by the Islamic militants and called on the international community to support the Iraqi people and government.
The council met in an emergency session, held behind closed doors, to address the dire humanitarian situation in northern Iraq caused by the Islamic State's advance, which included capturing the majority Christian city of Qaraqosh.
Before the Islamic State -- then known as the Islamic State of Iraq and the Levant (ISIL) -- seized large swaths of western and northern Iraq in June and declared a caliphate, Qaraqosh had a population of about 50,000 people, mostly Christians.
Islamic militants also seized the mostly Christian towns of Tall Kayf, Bartella, and Karamlesh.
They also claimed they had captured Iraq's largest dam, the Mosul Dam on the Tigris River, but a Kurdish official said the dam was still under their control.
Meanwhile, the United States says it is also expediting military assistance to Iraq's Kurdish Peshmerga forces, who are battling the Islamic militants.
A senior U.S. administration official told reporters on August 7 that the aid will supplement the Hellfire missiles, ammunition, and antitank shells Washington is delivering to Iraq's military.
The official, who spoke on condition of anonymity, did not specify exactly which types of weapons the United States was sending to the Kurdish forces.
The U.S. military withdrew from Iraq in late 2011 after nearly a decade-long presence.
Washington offered to keep a residual force in Iraq but could not agree with Iraqi officials on allowing U.S. forces to have immunity from prosecution.