Jihadists have dynamited bridges and mounted deadly attacks against previous supply convoys headed to the cut-off city of Djibo, leaving its people destitute.

But a security source told AFP that a convoy arrived on Tuesday after a three-week trek, braving roadside bombs and ambushes in which more than two dozen civilians, soldiers and jihadists died.

"A hundred trucks filled with food and basic necessities were able to reach Djibo yesterday under military escort," the source said.

Djibo resident Amsatou Dicko, speaking to AFP by phone, confirmed the arrival.

"There have been songs of joy in the town since this morning," she said. "Life has returned!"

Shops and the market have reopened, she said.

"We are going to be able to get supplies for a few days, even though prices are high."

One of the world's poorest nations, Burkina Faso is battling an insurgency that spilled over from neighbouring Mali in 2015.

More than 10,000 civilians, troops and police have been killed, according to one NGO estimate, and at least two million people have been displaced.

Djibo has become a regional hub for internally displaced people, with its population tripling to an estimated 300,000 people.

The trucks left the northwestern city of Kongoussi on February 28, a security official said.

But progress over the 95-kilometre (59-mile) route was slowed by improvised explosive devices (IEDs) and jihadist attacks.

Another security source told AFP that 15 IEDs had been defused along the way, and that the convoy had suffered ambushes.

Six soldiers, two civilians and 20 jihadists were killed, several sources said.

On the way, the convoy was able to resupply the blockaded town of Bourzanga on March 12

Idrissa Badini, a spokesman for civil society groups in Soum province, said it had been more than five months since Djibo had been supplied by land.

"There were small supplies by air, but the quantities were not enough for the hundreds of thousands of people," he said.

An earlier convoy had been forced to turn back in January, he said.

According to the United Nations, dozens of places in Burkina Faso face conditions similar to those in Djibo.

Jihadists effectively control about 40 percent of the country, according to official figures.

Anger within the military at failures to roll back the offensive led to two coups last year.