Iraqi soldiers manoeuvre sections of floating bridge on a muddy, man-made lake as American trainers instruct them in skills that have played a key role in the war against jihadists.
Green metal boats churn a frothy wake as they propel the sections before the Iraqi forces connect them together during the training at the Taji military base, north of Baghdad.
Members of the Iraqi army's Bridging Battalion who have completed the training are deployed in the area of Mosul, where government-led forces are fighting to retake the Islamic State jihadist group's last urban stronghold in the country.
Iraqi forces have deployed floating bridges on a number of occasions as they waged war against the jihadists in the "Land of the Two Rivers".
And floating bridges have a long history in Iraq, where boats were used to connect the two banks of the Tigris River at Baghdad from Abbasid times into the 20th century.
The Bridging Battalion "took part in a number of battles to support Iraqi forces in fighting (IS)," said Captain Ali Raad, an officer in the unit.
They have been deployed "in Anbar and Salaheddin provinces, and now in the battle of Mosul," Raad said, referring to provinces where three of the battles to retake cities from IS took place.
Iraqi forces in Mosul now face a major challenge: all of the bridges across the Tigris, which divides city into its eastern and western sides, have been damaged or destroyed.
When IS still controlled territory in east Mosul, having the bridges out of commission hampered jihadist activities.
But Iraqi forces have now retaken all of eastern Mosul, and have secured one bridgehead on the western side and are advancing toward another, meaning it is now in their interest to reconnect them.
- Providing 'essential' support -In the course of the training, the soldiers learn to "drive the combat bridge transporters, operate the boats, as well as construct the assault float bridge," said Staff Sergeant Michael McConaughey, a US soldier.
This exercise is overseen by American soldiers, but British troops are also conducting similar training at another site.
"There are currently about 90 (Iraqi soldiers) that are already trained and proficient, and with the addition of these 25, (there will) be over 100 ready to go complete bridge missions," McConaughey said.
The bridge can hold "up to a tank on the back of a truck that's on a trailer -- it can cross the heaviest vehicle we have," he said.
The utility of bridges that can be quickly established by the military became apparent fairly early in the conflict with IS, which overran large areas north of west of Baghdad in 2014.
IS used a bus bomb and an explosives-rigged boat to destroy two bridges leading to Dhuluiyah, a town north of Baghdad where tribesmen held out against the jihadists in one neighbourhood for months that year.
Haider Kadhim, a soldier in the Bridging Battalion, was shot in the stomach during the operation to set up a floating bridge across the Tigris to Dhuluiyah.
The tribesmen held, and the siege was eventually broken.
The unit lost one soldier and had five more wounded while setting up a bridge in Salaheddin province, but was still able to complete their task, Kadhim said.
Such bridges "are essential to provide logistical support and backing for forces during the battles," he said.