Special ops units have been active in Iraq well before raid to release prisoners

Daily Beast:

When Defense Secretary Ashton Carter announced Tuesday that the U.S. would begin "direct action" against Islamic State targets in Syria and Iraq, it sounded like a new mission for U.S. forces in a country where the president has repeatedly insisted Americans would not be engaged in combat operations.

But America's special operations forces have been engaging in these kinds of missions for several months, particularly in the Kurdish-controlled provinces in northern Iraq. And the special operations forces have already built up an extensive infrastructure to support these activities. This casts doubt on the official Pentagon statements that last week’s raid was “a unique circumstance.”

Since President Barack Obama authorized the first special operations teams to deploy to Iraq in the summer of 2014, the White House has provided few details on the mission and composition of the forces. The Pentagon today refers to the mission for the 3,500 U.S. service members as primarily "advise and assist," with an emphasis on training local forces. But the small and highly classified military footprint in northern Iraq shows the U.S. is more involved in the fight against the Islamic State.

According to U.S. and Kurdish officials, the U.S. now runs an operations center in Irbil staffed by a special operations task force whose work is so classified its name is a state secret. The task force has worked in recent months to identify and locate senior leaders of the Islamic State and participated in the mission last Thursday, in which a member of the Army's Delta Force was killed freeing prisoners from an Islamic State prison in Hawija. (He was the first U.S. soldier killed by enemy fire in the fight against the Islamic State.) These officials asked to speak on background because they were not authorized to disclose sensitive information about U.S. covert activities.

The secret U.S. military presence in northern Iraq doesn't end there. Highly trained American special operations forces known as Joint Terminal Attack Controllers, who help paint targets for airstrikes of Islamic State vehicles, camps and buildings, also operate in northern Iraq. U.S. officials tell us these controllers also work closely with other Western countries and the Iraqis to avoid collisions and direct air traffic for drones and other aircraft to support the mission against the Islamic State.

Finally, according to these officials, there is a contingent from the Marine Special Operations Command in charge of training Kurdish counter-terrorism forces fighting against the Islamic State.
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There is more.

Apparently the us has been trying to keep these operations secret for various reasons.  I suspect some of it had to do with operation security and force protection.  There were probably political reasons both in the US and Iraq for not publicizing the special ops forces in Iraq.  Obama still wants to act like he ended the war in Iraq and the Iraqis want to act like they don't need US help.