Dadaab, Kenya - They are coming in ones and twos, families and friends, on donkeys and in trucks, dressed in the clothes they were wearing when the mortars landed or the battlewagons buzzed through the streets outside their homes.

Thousands of Somalis in search of safety are arriving at an overcrowded aid camp over the border with Kenya in search of safety. More than 159,000 people have fled the capital, Mogadishu, in the latest upsurge in fighting.

Zamzam Hussein Farrah had to gather up as many of her children as she could find and run. Her journey to Dadaab – the world's biggest refugee camp – took her a month of hitching rides and walking.

"My husband went to the market and then there was fighting," says Ms. Farrah, sitting on a rickety wooden bench to begin the process of registering with the United Nations. "When the fighting started, we fled in different directions."

She arrived 11 days ago with four children. She has no idea where her husband is, or even if he is alive. There is no word, either, of her fifth child, who was with her mother.

There are dozens of similar stories among the families gathered around the simple wooden huts where they register for vaccinations, food, and shelter.

Al Shabab's brazen display of 'justice'

The latest fighting pitches the Islamist Al Shabab movement against the interim government, which has struggled to assert any authority since being formed in 2004. A moderate Islamist, Sheikh Sharif Sheikh Ahmed, won the presidency early this year.

Three years ago, his Union of Islamic Courts brought stability to Somalia before being defeated by Ethiopian troops. His Islamist background raised hopes that extremists could be brought back into the fold – hopes that have so far not been realized.

Al Shabab, considered by the US as a terrorist group with links to Al Qaeda, has taken over swaths of Somalia, as much through deals with local clan leaders as through force. On Thursday, its militants punished four men convicted of stealing cell phones and other items by cutting off a hand and a foot each.

It made for a brazen display of confidence, and the bloody spectacle was carried out in Mogadishu before hundreds of onlookers.

This week, the State Department confirmed the US was sending arms and ammunition to the government and would also help train its troops to fight the Islamist insurgents.

Congested camp, too many arrivals

But Dadaab – actually three camps in one – stands as a miserable testament to the world's failure to find solutions to Somalia's strife. More than 280,000 people are crammed into a congested jumble of mud-brick homes and tents.

When it was opened in 1991, no one believed Kenya would still be hosting Somalia's refugees almost two decades later.

The United Nations is desperately trying to find more land to accommodate the 500 people arriving here every day, but it faces resistance from a government and local authorities who view the new arrivals with suspicion.

The border remains shut, and Kenya has stepped up patrols to protect against Al Qaeda threats. Nairobi is constantly abuzz with rumors of terrorist attacks.

And the first wave of refugees, those who arrived with the collapse of Siad Barre's government in 1991, know they have little prospect of going back.

Saharo Sheikh Mohamed has not left the camp in 18 years. Her dream is to be one of the lucky ones relocated to the US.

"We would prefer any country where we could live peacefully," she says.