A mother guided her bawling five-year old boy across rocks close to Bambo, a town in eastern DR Congo, as mortar fire rained down nearby. 

It was midday on October 26 when the M23 rebels attacked the town, nestled in the hills in Rutshuru, North Kivu province.

An AFP team documenting the lives of people living on the frontlines of the M23 conflict was caught in the attack, leaving the town at the same time as its inhabitants.

Families broke into a run as rifle fire crackled overhead, jostling with crowds of people on the road out.

Panicked Congolese soldiers and policemen were pushing to get out ahead of the crush, fearful of falling into rebel hands.

AFP witnessed a soldier threatening to shoot a civilian unless he handed over his bag and phone.

"It's always like that with our soldiers, when we flee they steal our money and telephones," said the victim, a young man.

After lying dormant for years, the M23 launched an offensive in late 2021 and conquered swathes of North Kivu, displacing over a million people.

Rwanda backs the group, according to the United States and several Western countries, although Kigali denies the claim. 

United Nations drone footage from mid-October, viewed by AFP, showed columns of soldiers heading towards Bambo.

UN sources, who requested anonymity, said they were Rwandan military reinforcements. 

In the crowd fleeing Bambo, a man shouted: "A boy has just died". People pushed harder to get as far from the gunfire as possible. 

The victim was a 23-year-old named Hakiza, according to his uncle, interviewed by AFP later north of the town.

- Rebels -

A Tutsi-led group, the M23 traces its lineage to earlier rebel movements in eastern Democratic Republic of Congo.

Militias have plagued the volatile region for decades, a legacy of regional wars that flared in the 1990s and 2000s. 

In the early 2000s, earlier iterations of the M23 -- operating under a different name -- flitted between rebellions and periods of absorption into the Congolese army, a policy designed to neuter the threat it posed. 

The M23 was defeated militarily in 2013 after seizing the Congolese city of Goma, with many fighters taking refuge in neighbouring Rwanda and Uganda.

But the fighters took up arms again in 2021 demanding that the DRC honour a previously signed agreement foreseeing their integration into the army, among other issues.

The M23 has justified itself differently as the conflict has expanded. It now claims to defend the Tutsi minority in eastern DRC. 

According to the UN, hate speech and violence towards Congolese Tutsis has spiked alongside the M23 campaign.

- Ambush experts -

In Bambo, residents recalled the M23's arrival in November 2022. 

The army was thrown into disarray as the rebels seized the town of Kishishe, a few miles away from Bambo, in a matter of hours. 

M23 fighters then massacred 171 people in Kishishe, according to the UN. The victims were mostly men and boys accused of belonging to militias. 

Holding the hilly terrain around Bambo and Kishishe is important to the M23.

The area is a stronghold of the FDLR -- a militia created by Rwandan Hutu leaders who carried out the 1994 Tutsi genocide in Rwanda.

"They're good at ambushes, they kill a lot of M23s," explained a female Congolese soldier at a hotel in Bambo the day before the M23 attack. 

The DRC denies cooperating with the FLDR. 

But in Bambo, AFP saw FLDR fighters alongside Congolese soldiers and other militias.  

The soldier, wearing a khaki T-shirt emblazoned with a patriotic slogan, said it was important to work together to stop the M23 rebellion from spreading. 

Congolese soldiers fight in dire conditions. 

"We don't have bullet-proof vests, no binoculars, and when we throw a bomb, they throw 50 at us," said the 30-year-old. 

"Sometimes, we go 24 hours without eating," the woman said, adding that militias allied to the army resort to pillaging to feed themselves. 

- 'Left behind' -

In April, for reasons that remain unclear, the M23 withdrew from Bambo and Kishishe. The front lines several dozen miles from Goma were calm. 

But clashes erupted again in October, pushing 200,000 people from their homes, according to the UN's humanitarian arm OCHA. 

The Congolese army, assisted by European military advisors, has deployed artillery and war planes. 

The day before the M23 attack on Bambo, one Congolese army captain was fed up. 

"We're left behind here," he said, from a straw shelter by a road near the town.

"The government should tell us whether it's abandoned the east of the country, so that no more soldiers die for nothing".

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