The leader of the Islamic State, formerly Isis, has released the first audiotape calling for jihad since the group renamed. The group is currently battling Iraqi forces across large parts of the country.
President Obama has told congressional leaders he does not need to seek lawmakers' approval for any action the US may take in Iraq.
The Senate minority leader, Republican Mitch McConnell, told reporters Mr Obama had "indicated he didn’t feel he had any need for authority from us for steps that he might take".
The Iraqi government has asked the US to launch airstrikes on positions held by Islamist militant group Isis, although it is not yet clear exactly what steps the administration is considering.
US Vice-President Joe Biden has had discussions with Iraq's Prime Minister, Nouri al-Maliki, about measures "to roll back the terrorists' advances", according to a White House statement.
The Foreign Secretary has been clear on the threat of Isis, but he has ruled out the prospect of any UK military involvement in the crisis.
Iraq’s foreign minister, Hoshyar Zebari, is a natural diplomat. Polite, immaculately dressed, and blessed with a great memory.
Isis has paraded military equipment in Mosul it captured from when the Iraqi army fled in what some see as a "nightmare scenario."