Survivors told of their terror after they fled an attack by ISIS-linked extremists on a gas plant in Mozambique last month.
Thousands of people were forced to seek refuge after the coastal town of Palma was overrun and seized on March 24.
Several foreign companies were based in the area, which is home to a $20 billion natural gas project.
The true death toll remains unknown, but last week it was confirmed that British contractor Phil Mawer was among the casualties.
Eyewitnesses recounted their horror at seeing bodies, some decapitated, as they escaped to areas still under control of the Mozambique military.
"I had lost hope of living. Never in my life had I run so much," Mariamo Assane told AFP after she reached safety in Pemba, the capital of the northern Cabo Delgado province about 200 kilometres south of Palma.
Ms Assane, who is her 30s, recalled the grim sight of bodies scattered along the way as she fled.
Lionel Dyck, the owner of Dyck Advisory Group, a private military company helping Mozambican forces fight the extremists, told the BBC that when his team reached Palma on the first day of the attack "there were bodies lying on the road".
The corpses of some truck drivers delivering food aid were "lying next to their vehicles without heads", he said.
Heavily pregnant Fato Abdula Ali, 26, said she went into labour shortly after she and her two small children fled Palma.
As she trekked through the bush, the inevitable happened and she gave birth, on her own, before being taken to Pemba.
Lying on a hospital bed next to her newborn son Salimo, her eyes downcast, she recounted the "saddest moment" of her life when she had to abandon her children as she ran for her life.
Adding to the trauma, she said she does not know the whereabouts of her husband.
Nvita Nchute, 30, is another person lucky to be alive. He was taken by ship to Pemba last week, although he now doesn't know where his wife is.
He said he was at a local market when shooting started.
"I couldn't go back home to look for my wife," he said with tears streaming down his face, as he sat at a temporary shelter in Pemba's Eduardo Mondlane neighbourhood, popularly known as Expansao.
Morasse Ali, 26, said he spent four days in the bush without food or water.
"Those bandits arrived at my house, captured my family and took them away," he said. He has no idea if his wife and son are dead or alive.
The UN said it recorded nearly 10,000 civilians who made it to safety since the Islamist raid was launched on March 24.
The UN agency for migration said an estimated 23,000 survivors are gathered on the Afungi peninsula, near French energy giant Total's gas site, which is guarded by Mozambique's military.
The situation remains volatile and security concerns forced the UN on Friday to temporarily halt evacuation flights from Afungi to Pemba.
Muana Macasse Ali said his parents remain trapped in Afungi.
He said he hid in the bush "for three days without eating and even drinking water".
Mozambican military officials said that a significant number of insurgents were killed in the battle.
Total reportedly suspended operations at the plant, which was Africa’s biggest gas project.
"Total trusts the government of Mozambique, whose public security forces are currently working to take back control of the area,” the company said.