Obama says he has authorized U.S. air strikes against Islamic State 'if necessary'
President Barack Obama (AFP)

Washington (AFP) - President Barack Obama said he had authorized US forces to conduct air strikes against Sunni extremist militants in Iraq if they are needed to prevent a massacre of civilians.

"We can act, carefully and responsibly to prevent a potential act of genocide," Obama said, referring to a religious minority group besieged by fighters from the so-called Islamic State.

"I therefore authorized targeted air strikes if necessary to help forces in Iraq as they fight to break the siege and protect the civilians trapped there."

US military planes returned to the skies over northern Iraq on Thursday to deliver food and water to thousands of civilian refugees fleeing an onslaught by Sunni extremist militants.

A senior US defense official confirmed the mission had dropped "critical meals and water for thousands of Iraqi citizens."

All the planes returned safely after the food drop on an area outside the town of Sinjar where members of the Yazidi minority are besieged by fighters from the so-called Islamic State (IS).

[Image via Agence France-Presse]