A mother of five, Anna Sobie's wooden home is one of many that has been demolished in a shanty town in a lagoon in Lagos, with critics describing it as a land-grab by the authorities to gentrify the prime waterfront spot in Nigeria's biggest city.

Lagos State government officials deny the allegation, saying they are demolishing parts of Makoko - the country's biggest informal waterfront settlement - because it is expanding near high voltage power lines, posing a major health and safety risk.

Sobie and her children now sleep on the narrow broken platform where their house stood until a few weeks ago on Lagos Lagoon. This is the biggest of 10 lagoons in a mega-city that is facing an acute housing crisis - and where life is becoming increasingly expensive, pushing more people to the margins of society.

As Sobie spoke to the BBC, canoes - steered with paddles or long bamboo poles - moved through the narrow waterways, carrying mattresses and sacks of clothes belonging to the displaced people.

Residents say the demolitions began two days before Christmas, when excavation teams accompanied by armed police moved into sections of the waterfront settlement facing the Atlantic Ocean.

In a joint statement last month, 10 non-governmental organizations said that armed thugs, security personnel and demolition teams with bulldozers descended repeatedly on the community to tear down homes, and burn them.

Homes were set on fire with little or no notice, in some cases while residents were still inside, the NGOs added.

When the BBC visited Makoko, smoke, from the rubble of torched homes or from fires that people had lit, burning damp wood to dry their clothes, was hanging in the air.

Excavators were at work along the shoreline - houses built on wooden stilts over the lagoon were still being pulled down, their planks collapsing into the water below. Makoko was founded in the 19th Century by fishing communities who have lived in the settlement ever since, along with other low-income families and migrants who come to Lagos in search of better opportunities.

Ownership of the lagoon is fiercely contested. The state government claims ownership of it under federal law, saying Makoko has been built without planning permission or occupancy rights. Older residents dispute this, saying the settlement predates modern Lagos, and they have what they call a customary right to it.

Estimates of Makoko's population vary, from 80,000 to 200,000, but much of the settlement now lies in fragments. The NGOs said that more than 10,000 people have been displaced after the destruction of more than 3,000 homes, as well as schools, clinics and churches. The state government has not given any figures of the buildings demolished.

During the chaos of the demolitions, Sobie recalls: I was inside when it started... The noise was very loud. When we came out, we saw the excavator.

Like many other children, her son Solomon no longer goes to school. He now helps his mother gather firewood from collapsed houses, pulling loose planks from the debris to sell.

With the lagoon central to their lives, they have protested against the move to force them out of Makoko. More than 1,000 angry residents marched last week to the state legislature, demanding an audience with Governor Babajide Sanwo-Olu, whose offices are nearby. But police responded by firing tear gas, with protesters saying that at least one person was injured in the ensuing chaos.

Community leaders and residents say that tear gas was also fired during the demolitions a few weeks ago, causing the death of five people, including children. The Lagos State government says it is unaware of their personnel using tear gas or of deaths linked to the demolitions.

Speaking to the BBC, the state's commissioner for information, Gbenga Omotoso, says that any such claims would be investigated. Governor Sanwo-Olu defended the demolitions, stating they target homes built beneath high voltage power lines, asserting that No responsible government anywhere in the world can allow people to live directly under high-tension cables or obstruct vital waterways.

The locals argue that the demolitions are aimed at clearing the area for private developments, including luxury homes. Some residents suspect their homes have been demolished to pave the way for an upscale development.

In a statement, the NGOs express concern over a deliberate pattern of state-enabled violence against the urban poor, carried out to clear valuable land for elite interests and private mega-developments. The situation in Makoko reflects a broader housing crisis in Lagos, where demand for affordable housing far exceeds supply.