al-Shabaab are the group behind this terrorist attack on the Westgate shopping centre in
Nairobi.
The Somali extremist group killed scores and injured many more in the Kenyan capital, but
who are al-Shabaab and why is it that a Somali group is attacking Kenya?
al-Shabaab formed from the youth wing of the union of Islamic courts in 2006 and that's
what gives them their name, al-Shabaab means the youth.
al-Shabaab were led by Moalim Aden Hashi Ayro but he was killed in a US airstrike in 2008.
Now it's headed up by Ahmed Abdi Godane who's also known as Mukhtar Ali Zubeyr.
He's some Somaliland originally, an area to the north that declared independence from
Somali in 1991 but has never been internationally recognized as a nation state.
It's thought that al-Shabaab has between 7,000-9,000 fighters but the exact numbers aren't known
but many of them are foreign fighters.
"Are you happy in comfort in your country while your religion and your people are being
attacked?"
In 2012, al-Shabaab's leaders pledged allegiance to Ayman al-Zawahiri who's replaced Osama
bin Laden at the helm of al-Qaeda.
And there are fears that even more foreign fighters will flood into Somalia from Afghanistan
and Pakistan as a result of the military action there.
At the height of their power al-Shabaab controlled most of southern Somalia and the capital Mogadishu
and they enforced an extremely strict version of Sharia law.
There were regular reports of people being stoned to death for breaking the code and
other horrific punishments being metered out as well.
They lost a lot of their popular support after the famine in 2011 that's because they prevented
Western aid agencies from distributing food and that led to a lot of people dying.
Also there's the fact that many Somalis are Sufis but that hasn't stopped al-Shabaab from
destroying a large number of Sufi shrines, which again hasn't endeared them to the public.
Then in 2012 a group called Hizbul Islam split from al-Shabaab and has since renounced violence.
They'd only joined together in 2010 and recently more than 150 of the country's top Islamic
scholars declared a fatway towards the group because they say it's un-Islamic.
There have also been internal power struggles which Abdi Godane has dealt with pretty brutally.
Four of the groups top names and several other commanders have been 'dealt' with recently
and by dealt with I mean tracked down and killed.
It's not entirely surprising that there are these internal conflicts because as with most
movements there are several different but similar ideologies all competing together.
That and there's a $7 million bounty on Abdi Godane's head.
al-Shabaab still controls huge parts of the country especially rural areas but the African
union has been fighting the group on several fronts.
In 2011 it lost the capital of Mogadishu and then in 2012 the Port of Kismayo which Kenyan
troops played a vital part in taking.
And al-Shabaab has hit a number of foreign targets with terrorist attacks.
During the 2010 World Cup in South Africa they killed more than 70 people watching a
match in Kampala.
The Ugandan capital was chosen because, at the time, it was Uganda and Burundi providing
most of the troops to the African Union effort.
Kenyan troops have been fighting in Somalia for the past couple of years.
They got involved after a series of attacks and kidnappings of tourists and troops especially
in Northern Kenya.
That was putting tourists off visiting and tourism is a major component of Kenya's economy.
But the problem is that it's relatively easy for al-Shabaab fighters to get into Kenya
unnoticed.
And there have been a number of attacks on Kenya but this one on the shopping centre
is the largest.
al-Shabaab knows how important tourism is to Kenya so instead of going for a government
building, or attacking troops, they go for a civilian target and one where foreign nationals
are likely to be.
That strikes fear into people and governments around the world begin to warn people against
travelling there.
In fact Kenya President Uhuru Kenyatta has already pleaded with governments not to issue
travel advisories because, and here's the bit he didn't say, that would defeat the point
of Kenya's incursion into Somalia in the first place.