Amid concerns over a militant group's advancement toward the Iraqi capital, U.S. President Barack Obama on Monday notified Congress that up to about 275 U.S. military personnel were deploying to Iraq to provide support and security for U.S. personnel and the American embassy in Baghdad.

Obama said in a letter to Congressional leaders that the force, which began deploying on Sunday, has been sent "for the purpose of protecting U.S. citizens and property, if necessary, and is equipped for combat."

"This force will remain in Iraq until the security situation becomes such that it is no longer needed," Obama wrote.