Story highlights Currently, there are 4,565 US troops in Iraq

President Barack Obama and Iraqi Prime Minister Haider al-Abadi have a deal to increase those levels

(CNN) The US and Iraq have agreed on a plan that could send approximately 500 additional US troops to Iraq in the coming days to assist Iraqi forces in the battle to retake Mosul from ISIS.

The plan has been under discussion for weeks but President Barack Obama and Iraqi Prime Minister Haider al-Abadi have now agreed on the details, a US defense official tells CNN.

"In consultation with the Government of Iraq, the US is prepared to provide additional US military personnel to train and advise the Iraqis as the planning for the Mosul campaign intensifies," the official said.

This is expected to be the final addition of US military troops in Iraq, according to officials. Currently, there are 4,565 US troops in Iraq. The approved ceiling is of troops is 4,647. The Iraqi government generally has to approve and agree to any significant change in US troop levels. There are also hundreds of additional troops in Iraq on so-called temporary duty status that may only involve weeks or months of deployment.

The US troops are to be based largely in northern Iraq at various locations. US officials have indicated as the battle for Mosul unfolds some small teams of US military advisers are likely to be placed closer to combat than previously but not at the front lines.

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