The two leaders talked about the latest developments in the unfolding crisis and Harper expressed Canada's willingness to do more on the humanitarian aid front.
Jason MacDonald, a spokesman for Harper, says the pair agreed on the need to confront the terrorist threat posed by the al-Qaida splinter group known as the Islamic State of Iraq and the Levant.
The group has already swept across northern and eastern Iraq, occupying almost one-third of the country.
MacDonald says Harper indicated Canada is ready to offer additional help, and that Canadian officials will work with their counterparts to identify additional avenues for humanitarian relief.
On Sunday, the federal government said it would send $5 million in additional emergency supplies and humanitarian aid to Iraq, including food, medicine, cooking materials and blankets.
Harper and Obama also shared the hope that a new, inclusive Iraqi government would be able to unite to counter the current crisis.