PEMBA: Thousands of Palma residents remained stranded on Tuesday, hiding around the besieged northern Mozambique town and scrambling to escape the area overrun by violent jihadist militants last week, sources said.

Insurgents affiliated with the Islamic State group (IS) launched a raid on the coastal town last Wednesday, ransacking buildings and murdering and beheading civilians.

Dozens have been killed in what witnesses describe as a coordinated attack, just 10 kilometres (six miles) from a multi-billion dollar gas project led by France's Total.

Shaken survivors have since streamed into the neighbouring town of Mueda and regional capital Pemba, where they arrived via boat, foot and plane.

But sources told AFP thousands were still wandering around Palma, desperate to find refuge.

Some trudged days through surrounding forest, walking west towards Mueda and north to reach the Tanzanian border.

Hundreds more travelled to the Afungi peninsula, the site of the gas exploration project, where they gathered outside Total's fortified complex, UN workers told AFP.

Total ferried around 1,400 people, including both gas and government workers, to Pemba on Sunday, but has since been accused of turning its back on desperate residents.

Only a few dozen other survivors have reached the regional capital, mainly on small fishing boats, raising concern among humanitarians on the ground.

"That's very little compared to the thousands that are reported stranded in Palma," said one aid worker who did not wish to be named.

"We are worried that so far very few are coming."

She told AFP around 5,000 escapees had reportedly assembled close to a lighthouse on the peninsula.

"Those are probably not the only ones," she added.

Total said it has organised "emergency support", including food and water, for people arriving at its site.

In Pemba, aid workers and missionaries waited outside the port for arrivals while others assisted the dozens who had managed to complete the journey.

"Many of them had been hiding for more than four days," Father Kwiriwi Fonseca told AFP.

"Some of them were injured, most of them were suffering from hunger."

Survivors asked locals if they had seen their missing relatives.

"They are extremely desperate and worried because Palma's mobile network is down," said resident Anda Assane.

"They have not had news from their loved ones for several days."

Pemba is already packed with hundreds of thousands of other people displaced by the Islamist insurgency, which has uprooted nearly 700,000 from their homes across the vast province.

The attack on Palma is the biggest escalation of an insurgency that has wreaked havoc across northern Mozambique since 2017, with jihadists raiding villages and towns with the aim of establishing an Islamic caliphate.

The bloody campaign has claimed at least 2,600 lives, half of them civilians.

The United Nations said "sporadic clashes" were still reported from Palma on Tuesday morning.

"We expect that thousands more people are making their way by foot, boat and road to reach safer destinations," its humanitarian affairs branch said in a statement.

"They will require urgent assistance at their destinations."