President Barack Obama
President Barack Obama Reuters

The US has sent in over 500 marines, dozens of helicopters, and the aircraft carrier George HW Bush into the Persian Gulf Tuesday, according to CNN.

According to the Guardian, around 170 of those forces have already arrived in Iraq, and another 100 soldiers will be on standby until needed. In addition, officials told Reuters Tuesday that the White House was considering sending a contingent of special forces to train and advise Iraqi troops, many of whom have fled their posts.

The numbers keep swelling in the Iraq crisis, with the US increasingly adding manpower - despite a commitment not to join the fray. 

Earlier this week, US President Barack Obama stated to Congress that he would only deploy "up to 275" men in Iraq, which is suffering from the lightning-fast advances of Islamist group Islamic State of Iraq and the Levant (ISIS). 

The statement follows an interview with US Secretary of State John Kerry with Yahoo! News Monday, where he admitted that the US was seriously considering airstrikes as a military option. 

"Well, they are not the whole answer but they may well be one of the options that are important to be able to stem the tide and stop the movement of people who are moving around in open convoys and trucks and terrorizing people," he said. "When you have people murdering, assassinating in these mass massacres, you have to stop that and you do what you need to do."

The move puzzled both the public and political analysts, after Obama stated just days earlier that the US would not be sending troops to Iraq.

"We will not be sending US troops back into combat in Iraq," Obama stated on the White House lawn Friday. "This is not solely, or even primarily, a military challenge."

On Thursday, Obama declared that short-term military actions will have to be taken in Iraq and said he is looking at "all options", but his spokesman later clarified the president did not intend to send ground troops to Iraq.

The move comes in the wake of the takeover of several Iraqi cities by ISIS, including Mosul and Tikrit.