US military operation in Iraq limited in scope and duration: Obama

He added that he also authorised US Armed Forces to provide humanitarian assistance in Iraq

The American military operation in parts of Iraq against the Islamic State terrorists is "limited in scope and duration", US President Barack Obama has informed the Congress.

In a letter to John Boehner, Speaker of the US House of Representatives, on War Powers Resolution regarding Iraq, Obama said he has authorised the Armed forces to conduct targeted airstrikes in Iraq.

"These military operations will be limited in their scope and duration as necessary to protect American personnel in Iraq by stopping the current advance on Erbil by the terrorist group Islamic State of Iraq and the Levant and to help forces in Iraq as they fight to break the siege of Mount Sinjar and protect the civilians trapped there," he said.

Thousands of families from the Yazidi minority community are reportedly trapped in the mountains without food and water after fleeing the rampaging fighters of the Islamic State, also known as Islamic State of Iraq and Syria or ISIS.

Following Obama's orders, the US military yesterday targeted Islamic State installations in Iraq.

Obama said he has also authorised US Armed Forces to provide humanitarian assistance in Iraq in an operation that commenced on August 7.

These operations will also be limited to supporting the civilians trapped on Mount Sinjar, he said.

"I have directed these actions, which are in the national security and foreign policy interests of the United States," he said, adding these actions are being undertaken in coordination with Iraqi government.

Earlier, Vice President Joe Biden called Iraqi President Fuad Masum to discuss US military operations in northern Iraq and the ongoing government formation process in Baghdad.

Biden reiterated Obama's commitment to assist and protect innocent Iraqi civilians trapped on Mount Sinjar and bolster Iraq's ability to fight the ISIS, the White House said.

Biden affirmed the US commitment to support Iraq and all of its citizens - from north to south - as they work to defend the country against this international threat.

Meanwhile, US Deputy National Security Advisor Ben Rhodes met with members of the Iraqi Yezidi community to discuss the dire humanitarian situation in northern Iraq, said Deputy Spokesperson of National Security Council Bernadette Meehan.

Rhodes discussed Obama's decision to conduct airdrops of food and water to the Yezidi and other civilians trapped on Mount Sinjar and to authorise targeted airstrikes to help break the siege of Mount Sinjar, she said.

"He emphasised that the United States will continue to pursue a strategy that empowers Iraqis to confront this crisis, including by providing urgent assistance to Iraqi government and Kurdish forces," Meehan said.

In a travel warning, the State Department warned US citizens against all but essential travel to Iraq.

"Travel within Iraq remains dangerous given the security situation," the travel warning said.