US President Barack Obama says his government is looking at "all options", including military action, to help Iraq fight Islamist militants, Radio New Zealand reports.
His remarks came after the cities of Mosul and Tikrit fell to Sunni Islamist insurgents during a lightning advance.
Barack Obama said Iraq was going to need more help from the United States and the international community.
Led by the Islamic State in Iraq and the Levant (ISIS), the insurgents are believed to be planning to push further south to the capital, Baghdad, and regions dominated by Iraq's Shia Muslim majority, whom they regard as "infidels".
President Obama said the United States had an interest in making sure jihadists did not gain a foothold in Iraq.