Small, battered metal boats crowd a muddy landing site on the Tigris River, taking on goods and passengers for the trip to an Iraqi area jihadists have besieged for months.

The steady stream of the boats, piloted by Iraqis who brave shelling and sniper fire, has played a key role in supplying the Jubur area in the town of Dhuluiyah across the river, helping keep alive resistance against the militants.

The boats at the landing site in the Balad area, north of Baghdad, are loaded with items ranging from tomatoes and cooking gas to ice, while passengers gingerly step aboard, careful not to upset the narrow, unstable watercraft.

Small outboard engines send smoke drifting across the swirling green-brown river as the boats arrive and depart, and more wait nearby at an island of towering reeds.

Residents of the Jubur area have taken up arms alongside security forces and fought off jihadists from the Islamic State (IS) group, who hold surrounding territory after leading a sweeping offensive that overran much of Iraq's Sunni Arab heartland in June.

The boats, which also carry people out for medical treatment, have been "the vital route," without which Dhuluiyah would have completely fallen, says Abed Mutlak Mohammed, a senior leader in the Jubur tribe, for which the area is named.

The men who now spend their days piloting the boats come from a variety of professions, such as Nadhim Issa Obaid, who was an education ministry employee when the conflict broke out.

- 'Many dangers' -

Fees for transport are small, especially considering the threats the boats face -- less than a dollar for passengers, and roughly four for goods, he says.

"There are many dangers," Obaid says.

The boats are exposed to shellfire at landing sites on both sides of the river as well as while they make the crossing, and they also run the risk of snipers.

"The most important thing is to deliver the passengers safely," says Arkan Abdullah, a policeman who operates another boat.

On one trip, "I was carrying five passengers... A mortar (round) fell 20 metres away," he says.

It did not cause any injuries, but others have not been so lucky -- Mohammed says a shell killed a child and wounded four people last week.

Once the boats are loaded with goods or passengers, they go downstream from the landing site, hook around the end of the nearby island and then head upstream and across the river to Dhuluiyah.

The men know the route well, moving slowly near the bank in some places and speeding up in others in an effort to avoid any snipers watching the river.

Once on the Dhuluiyah side, there are multiple landing sites among the tall reeds where they can unload cargo and passengers.

Then they head out again onto the Tigris for another run to the militant-besieged area, sending small waves rolling back toward the bank.

"God willing, we will be victorious," Abdullah says.