Somalia: Al-Shabab remains a potent threat
Somalia's al-Shabab militants have said they carried out the attack on a Nairobi shopping centre in "retribution" for Kenya's efforts to help the Somali government. Kenyan troops are part of the African Union force in the country. Despite losing ground, al-Shabab remains a potent threat as the BBC's Mark Doyle reports from Kismayo - once the group's main base.
On a bright, moonlit night at Kismayo airport, the crack-and-whizz of high-velocity bullets suddenly pierces the silence.
"Incoming fire!" someone shouts.
The "crack-whizz" then gives way to the deeper "thud-thud-thud" of the airport defender's heavy machine guns.
It is probably an attack by the Islamist al-Shabab militia.
Defending the airport are troops of the African Union force in Somalia, Amisom.
I carefully climb up to a high position and see a light a kilometre or two away to the south. It looks like car headlights rising and falling on a bumpy track.
Then the mortars start: "crump-whoosh, crump-whoosh". Definitely outgoing fire. Possibly towards that moving light.
Then suddenly silence returns.
It was an interesting few minutes. But it was the symptom, not the cause.
If you want to understand Somalia, Dr Abdisamad Abubacar Haji of the Kismayo General Hospital is a useful person to meet.
"Our main issue is not a lack of drugs," Dr Haji says, blowing away the usual story of poverty and shortages I was expecting at the run-down hospital.
"No, the main problem here is security. It is sometimes difficult to treat your patient because he might kill you."
I was in a hospital ward with rough concrete walls and beds without proper sheets. The dirty windows allowed in only a little light.
The ward was full of patients with blast- or bullet-wounds from a car-bomb assassination attempt a couple of weeks ago.
On one bed was a man whose legs had been shattered by the explosion. He was wired up all along his body in a primitive splint. I doubt he will ever walk properly again.
The target of the attack was warlord Ahmed Madobe, the leader of the region around Kismayo, known as Jubaland.
Mr Madobe survived the attack; he was reportedly in a bullet-proof car. More than 20 other people were killed.
The death toll remains vague as the medics could not account for all of the pieces of flesh they gathered at the scene.
Dr Haji's "problem", as he delicately put it, was when he conducts the triage of incoming wounded.
"When you have so many people to treat," the wiry, bearded Dr Haji says, "they are all shouting 'Treat me first! Treat me first!'
"But we are doctors and our training tells us we must treat the most serious cases first. So whoever we judge should be second or third in line might get angry and attack us - or even kill us."
Absence of aid
We left the hospital in a heavily armoured African Union convoy, with soldiers from the West African state of Sierra Leone.
It is not possible for foreigners - or even, often, Somalis - to travel safely without armed guards. The possibility of kidnap or roadside bombs is very real.
We arrived on the edge of Kismayo, at a camp for people made homeless by the war - refugees in their own country.
You can find these all over Somalia. Here, there was no sign whatsoever of any aid agencies helping.
Children played in the twisted carcass of what was once a car sat on a mound of rubbish.
The people lived in shacks made of sticks and plastic bags. The lucky ones have the odd corrugated iron sheet.
Moussa Ali, who lives in this filthy camp, used to be a farmer near the town of Djilib, north of Kismayo.
He was well-off by Somali standards.
"I had a seven-roomed house and a 20 hectare plot. I grew sesame seeds, beans and mangoes," he says.
But he abandoned all this because of what he said was the unbearable oppression of living under al-Shabab.
"They wouldn't let my girls go to school," he says.
"Every time I made a bit of money they made me give them half in Zakawat (tax for their cause). If I refused, they threatened to kill me."
Somalia has suffered for decades from a proliferation of firearms and deep-seated clan animosities.
Somalia doesn't have "tribes" like the rest of Africa. Everyone here is "ethnic Somali".
So instead their forum for disputes is the clan.
In southern Somalia, the main current dispute is between the Ogadeni and Marehan sub-clans.
But it has been overshadowed and internationalised by al-Shabab, which has exploited the latent clan warfare and taken control of about half of southern and central of Somalia.
Enter, in 2007, Amisom - the 17,000-strong African Union Mission in Somalia - made up of soldiers from several African nations.
Amisom is paid for by Western countries because they do not want another Afghanistan. Al-Shabab is allied to al-Qaeda.
The thoughtful and bespectacled Brigadier Antony Ngere is the Kenyan commander of Amisom's southern sector.
In 2009 and 2010 Kenya suffered attacks and kidnappings originating from across the border in Somalia.
"The Kenyan army is in Somalia to check and, if possible, eliminate al-Shabab", Brig Ngere tells me.
"We have liberated important parts of the south and could do more - but we lack enough troops or equipment".
I put it to Brig Ngere that Kenya was in fact more interested in protecting its own border - and potentially creating a useful buffer state in southern Somalia under the leadership of Ahmed Madobe - than it was in bringing peace to the whole country.
"That is not true", he says. "We do have a very long border with Somalia, which we have to protect. But we are not creating any buffer state.
"We need the international community - the aid organisations - to come to the aid of the suffering Somali people," says Brig Ngere.
I did not personally see a single foreign aid worker operating on the ground in Kismayo.
"We are in control of Kismayo. Now we plead with the aid agencies to come and help."