President Obama Authorizes Airstrikes in Iraq (FULL SPEECH)

Washington (CNN) -- U.S. President Barack Obama said Thursday that he's authorized "targeted airstrikes" in Iraq to protect American personnel and help Iraqi forces.

"We do whatever is necessary to protect our people," Obama said. "We support our allies when they're in danger."

A key concern for U.S. officials: dozens of American consular staff and military advisers working with the Iraqi military in Irbil, the largest city in Iraq's Kurdish region.

Obama said Thursday he'd directed the military to take targeted strikes against Islamist militants "should they move towards the city.

Rapid developments on the ground, where a humanitarian crisis is emerging with minority groups facing possible slaughter by Sunni Muslim extremists, have set the stage for an increasingly dire situation. Thousands of families from the Yazidi minority are reportedly trapped in the mountains without food, water or medical care after fleeing the rampaging fighters of the Islamic State, also known as Islamic State of Iraq and Syria or ISIS.

Throngs of refugees, many of them Iraqi Christians, are on the run -- their largest city, Qaraqosh, now occupied by fighters who gave them an ultimatum, "Convert to Islam or die. Obama also said he'd authorized targeted airstrikes "if necessary" to help Iraqi forces protect civilians trapped on the mountain.

"When we face a situation like we do on that mountain with innocent people facing the prospect of violence on a horrific scale, when we have a mandate to help, in this case a request from the Iraqi government, and when we have the unique capabilities to help avert a massacre, then I believe the United States of America cannot turn a blind eye," Obama said. "We can act, carefully and responsibly to prevent a potential act of genocide."

The potential escalation of U.S. military involvement comes two years after Obama ended the Iraq war and brought home American forces.

White House spokesman Josh Earnest told reporters Thursday that there is no chance of ground troops heading back.

Obama acknowledged that many Americans are concerned about military action in Iraq.

"As Commander in Chief, I will not allow the United States to be dragged into fighting another war in Iraq, so as we support Iraqis as they take the fight to these terrorists, American combat troops will not be returning to fight in Iraq because there is no American military solution to the larger crisis in Iraq," Obama said.

The President's announcement that he'd authorized airstrikes came after the United States airdropped meals and water in Iraq, sending humanitarian aid to trapped minority groups.

"The mission was conducted by a number of U.S. military aircraft under the direction of U.S. Central Command," a senior U.S. defense official said. "The aircraft that dropped the humanitarian supplies have now safely exited the immediate airspace over the drop area."