WASHINGTON, Aug. 7 (Xinhua) -- U.S. military planes has flown over northern Iraq on Thursday to drop humanitarian supplies to thousands of Yazidi minority fleeing attacks by Islamic State extremists, 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," he said.
Later, the White House said U.S. President Barack Obama is to make a statement on the Iraq crisis at 9:30 p.m. ET on Thursday (0130 GMT Friday).
As many as 40,000 religious minorities in Iraq have been dying of heat and thirst on a mountaintop following death threats from the Islamic State, the New York Times reported.
Obama has been weighing a series of options ranging from dropping humanitarian supplies on Mount Sinjar to military strikes on the extremist fighters now at the base of the mountain, the newspaper quoted a senior administration official as saying.
"The situation is nearing a humanitarian catastrophe," White House spokesman Josh Earnest told a press briefing on Thursday. "We are gravely concerned for their health and safety."
However, he declined to confirm whether Obama is mulling any military options, reiterating there would be no American combat troops in Iraq and that any military action would be extremely limited.
Earnest said Obama had made clear in the past that any U.S. military action would be "very limited in scope," would not involve putting troops on the ground, and should be closely tied to Iraqi political reforms, which Washington has demanded.
Meanwhile, the U.S. Defense Department also kept silent on the issue related to the airstrikes by U.S. forces.
The Islamic State militants have swept Iraq's north recently and seized the nation's largest dam Thursday, which provides essential supply of power and water to the region as well as access to the river that runs through the heart of Baghdad.