Terror group Boko Haram has captured another town in Nigeria's north-east, hours after it allegedly carried out an attack which killed at least 45 people.

There were apparently no men or soldiers left to defend the town of Damasak in Borno state, after hundreds of residents fled their homes.

The incident occurred a few days after reports said the terrorists had killed "scores of civilians" in the town.

Some witnesses told news agency AFP the militants had entered the town disguised as soldiers before attacking traders in the market.

"There is not a single male in Damasak. Boko Haram is in control because all males and soldiers have fled. No one expects women to fight them," Maina Ma'aji Lawan, who represents northern Borno state in Nigeria's Senate, said.

Usman Kalil, a senior local government official, said Boko Haram had hoisted their flag in the town.

"They have killed our people at will but I don't know how many people," he said.

Who are Boko Haram militants?

Boko Haram, which fights against Western influence in Nigeria and aims to impose its version of sharia law in the country, declared an Islamic caliphate in Gwoza, along the Cameroon border, in August 2014.

The group has been raiding several cities in the north of the country in a bid to take control of more land.

Violence linked to Boko Haram's insurgency has resulted in an estimated 10,000 deaths between 2002 and 2013.

"They also destroyed many buildings, including the market, a hospital and the secretariat. Many people, especially women and children, are under the custody of the terrorists."

Elsewhere in Borno, Boko Haram ambushed around 48 fishermen, killing them in sickening fashion by tying them up and throwing them into Lake Chad.

A few days before, the militants had entered the village of Doron Baga and massacred civilians with guns and knives. Hundreds of people have died in the three incidents.

Boko Haram carries out its attacks mainly in northern Nigeria, where Borno and other two states, Yobe, and Adamawa, have been under a state of emergency since May 2013.

Boko Haram's fresh attacks came weeks after the Nigerian government announced it had reached a ceasefire with the terror group.

Critics cast doubts over the ceasefire, as Boko Haram's leader Abubakar Shekau did not release any official statement regarding the truce.