A delicate woman wearing a white scarf over her head, Dr Hawa Abdi speaks in halting English, occasionally leaning forward from an overstuffed armchair in a quiet apartment in Nairobi and tapping a brown notebook to make a point.

In 2010, Glamour magazine voted her one of their Women of the Year, describing her as "equal parts Mother Teresa and Rambo".

For Abdi is one of Somalia's most famous figures – a 65-year-old gynaecologist known at home as Mama Hawa. In Somalia, she founded the Dr Hawa Abdi Foundation, which runs a camp and hospital that provides food, education and medical care to the landless. The camp, 12 miles from the capital, Mogadishu, in the Afgooye corridor, is home to up to 90,000 people on land that has been in Abdi's family for generations.

But militiamen recently confiscated part of the land surrounding the camp.

"Bit by bit, they are taking my land so I no longer have space to welcome the poor people," said Abdi.

This happened shortly after world leaders met in London to promise support for Somalia, and is a reminder of how difficult it is to work in areas controlled by the Islamist rebels of al-Shabaab. Abdi said an al-Shabaab court ruled at the end of last month that the confiscated land, which was home to 400 people, now belonged to one of the group's associates.

Since that ruling, many people have fled the camp, heading to Mogadishu. These are joining thousands fleeing an expected assault on al-Shabaab by African Union troops, who now control most of Mogadishu.

One of the stated aims of the African Union mission in Somalia (Amisom) is to clear the way for humanitarian organisations to reach people in the al-Shabaab-controlled south, still suffering the worst effects of last year's drought and famine, which killed tens of thousands.

The militant group, which despises foreign intervention, has expelled numerous international and local aid groups from the territory it controls. The United Nations refugee agency said on 17 February that more than 7,200 people had fled the Afgooye corridor in the previous two weeks. The 25-mile stretch of road is home to almost 410,000 displaced people.

Al-Shabaab has imposed a harsh form of sharia law in the southern part of Somalia. Punishments include beheadings, stonings and "cross-amputations" (cutting off a hand and the opposite leg). And although some analysts believe the movement is weakened as it faces a three-pronged assault from Kenyan, Ethiopian and African Union troops, Abdi says the situation is very bad.

"Now is the worst time; [al-Shabaab] don't want young boys to play football, they don't want them to see television, they don't want them to dress normally. They killed one because he was smoking in Afgooye," she says. "These people, we don't know what they want or where they come from."

The court ruling is just the latest attempt to squeeze Abdi off her land. Last October, militiamen arrived with workmen and cleared some of her land and adjoining territory to build storage units. Before that, in 2010, fighters from Hizb al-Islam attacked her camp and ordered her out.

She refused, telling them: "I'm a doctor. What have you done for society?" Eventually, under international and local pressure, the militants released her. Abdi left Somalia and handed over the administration of the camp to her youngest daughter, Amina.

The camp, which Abdi started as a clinic in 1983, has a 400-bed hospital, a school for around 700 children, wells and a farm. She has tried to provide food and water to the thousands living there, using her own money and funds from donors.

Abdi says Somalis have to solve their own problems, but that the international community must give financial support. Otherwise, any reconciliation is doomed to fail.

"I hope that in the next few months, I will be operating freely in my place and no one can take away my land," she said. "If al-Shabaab leave, as [is] the Somali habit we will go and sit under the trees, we will talk about the region, among the clans, and the problem will be solved. Only the Somalis can do it, but with economic support."

Abdi says she and her two daughters, Amina and Deqo Mohamed, both doctors, would like to return home. "At night I dream about going to where I played when I was still young."