President Barack Obama has ordered 275 U.S. military personnel to Iraq to help provide security to the embassy in Baghdad and U.S. personnel there.
Mr. Obama's notification to Congress Monday says the move has the consent of the Iraqi government.
While the president has ruled out sending ground forces back into Iraq, he met with his national security team Monday to consider other options.
They include possible air strikes against the Sunni militants who already control large parts of northern Iraq and have vowed to seize Baghdad from the Shiite-led government.
The U.S. also is considering working with Iran. But the Pentagon says it has no plans to enter into military cooperation with the Iranians in any action in Iraq.
A top State Department official says U.S. and Iranian diplomats met briefly Monday on the sidelines of nuclear talks in Vienna. The official says talks with the Iranians will not include any discussion of military coordination.