Carter, who is currently in Iraq on an unannounced visit, said on Monday that 560 more US troops will be sent to Iraq, which will help establish the newly retaken air base in the town of Qarayyah as a staging hub for the long-awaited battle to recapture Mosul from ISIS militants.

“These additional US forces will bring unique capabilities to the campaign and provide critical enabler support to Iraqi forces at a key moment in the fight,” Carter said, adding, "The additional troops will provide a range of support for Iraqi security forces, including infrastructure and logistical capabilities at the airfield near Qayyarah".

On Saturday, Iraqi government forces fully liberated the strategic airbase in Qarayyah, a town located some 60 kilometers (40 miles) south of Mosul, from ISIS militants.

The photo shows the Qayyarah airbase, following its recapture by Iraqi forces from Daesh militants on July 9, 2016.

The move to increase the number of US troops comes despite growing concerns among the Iraqi public that the US is planning to use battle against ISIS as a pretext to return to Iraq. US forces invaded Iraq in 2003 to topple long-time dictator Saddam Hussein but the large-scale military operation deteriorated security in the Arab country and gave birth to various militant groups.

The increase announced on Monday will bring the number of US troops in Iraq to more than 4,647. US President Barack Obama had announced three months ago that he planned to send more troops to Iraq.

Carter said most of the troops will go to Qayyarah, adding that they will help Iraqi security forces planning to encircle and eventually retake the key city. A team of American troops went into Qayyarah for a quick site assessment on Sunday and left.

Visiting US Defense Secretary Ash Carter, (C-L), accompanied by the Iraqi Defense Minister Khaled al-Obeidi, (C-R), arrives to the Ministry of Defense in Baghdad, Iraq, July 11, 2016. (AP photo)

“Iraqi Security Forces … will complete the southern-most envelopment of Mosul. That's its strategic role, and that's its strategic importance,” Carter told reporters before arriving in Baghdad.

The top US defense official had called the recapture of Qayyarah a key strategic victory.

Carter’s announcement comes as Iraqi forces prepare to retake Mosul, Iraq’s second largest city and the capital of the northern province of Nineveh, which fell to the hands of ISIS in June 2014.

The US and allies formed a so-called international coalition against ISIS in late 2014, with the ostensible aim of targeting positions of the group in northern and western Iraq. The coalition air strikes were later expanded to purported ISIS-held territories in neighboring Syria, despite criticism by Damascus that the attacks violate the Arab country’s sovereignty, Press TV reported.

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