More US troops to join Mosul battle
The United States will send 560 more troops to Iraq to help establish a recently retaken air base as a staging hub for the battle to recapture Mosul from Isil militants.
US defence secretary Ash Carter revealed the deployment on an unannounced visit to the country.
Most of the new troops will be devoted to the build-up of the Qayara air base, about 65km south of Mosul, and will include engineers, logistics personnel and other forces, Mr Carter said.
They will help Iraqi security forces planning to encircle and eventually retake the key city.
He said: "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."
Mr Carter revealed US president Barack Obama's decision as he spoke to about 120 troops in a building at Baghdad's airport.
Many were members of the 101st Airborne Division, known as 'the Screaming Eagles'.
The increase brings the total US force authorisation in Iraq to 4,647, and comes just three months after Mr Obama's last troop addition.
Mr Carter told reporters earlier that US advisers are prepared to accompany Iraqi battalions if needed, as those units begin the siege of the key northern city.
One potential job is helping Iraqi troops use highly technical bridging capabilities to get across the river into Mosul.