The protests came just days after the government said the country's security forces had killed more than 100 suspected members of the Islamist terrorist group al-Shabab, which is linked to the killings of 28 passengers who died in an attack on a bus on Saturday.

DW: The insurgents who carried out the massacre on Saturday fled on foot. How likely is it that Kenyan security forces caught the ones who were actually involved in the killings?

Andrews Atta-Asamoah: So far, it has been very difficult to verify. We have claims from the government that up to 100 of the militants were killed in a Kenyan military response and we have also heard from al-Shabab a denial of that happening. Subsequently, there have been some portrayals emerging from the Kenyan media to the effect that it didn't really happen. So it has been the word of al-Shabab against that of the government. I think it is quite difficult at this time to independently verify anything. The government is saying that they responded by hitting their base. If you look at the fact that the attackers escaped on foot, it's possible that the government may have done it. But then it is also difficult to prove at the moment that the actual perpetrators were the ones who were hit and killed.

Do retaliatory incursions by the Kenyan security forces discourage al-Shabab from carrying out attacks? What has happened in the past?

So far al-Shabab doesn't seem to be deterred by a killing of their mujahedin, as they call them, because their philosophy of operation is quite different from that of conventional forces, who do not necessarily want to lose fighters. Al-Shabab has many of the type of fighters who are ready for jihad and so do not necessarily fear to die. We have seen that even though particularly AMISOM in Somalia has succeeded in killing several of them, this has not deterred them from operations and from killings. I think retaliatory attacks upon retaliatory attacks lead to more. And this is exactly what is happening. I think the solution does not lie in retaliatory attacks; the solution really lies in having a comprehensive response to the rising insecurity trend in Kenya and in the larger region.

Why are the Kenyan authorities unable to prevent these attacks?

One of the biggest issues is the fact that the Kenyan-Somali border is quite porous. And then there's also a huge structural weakness in Kenya. Many of these actors are easily able to cross on to the Kenyan side and do many of these things. We have also seen that over the years al-Shabab has been able to penetrate many aspects of Kenyan society. So they are able to get information; they are easily able to lay ambushes. But more importantly, the fact that there are certain transnational identities between Kenya and Somalia makes it very difficult for one to do just ethnic profiling of people, because it is very difficult to differentiate between a Somali and a Somali Kenyan.

Many of these are structural difficulties. That makes it difficult for Kenya to respond.

Kenya also has a lot of challenges with its security forces. At the moment they are stretched quite thin. If you look at the sort of vehicle that was ambushed, one would have thought that by now many of these long-distance buses, which are transporting so many people and which are really vulnerable, would have at least had security forces present on them or highway security accompanying them. But nothing like that is happening. So many groups like al-Shabab are actually exploiting more and more of Kenya's structural vulnerabilities.

Does al-Shabab have many sympathizers in Kenya?

It is difficult to measure at the moment, because we know that in the northeastern corner of Kenya al-Shabab has really been attacking many places. And we do know that they've also been able to recruit over the years. There are Kenyan fighters in al-Shabab's ranks. We know that they have huge sympathizers along the coast. There are even some religious leaders who recruit openly for them. There is an organization which has declared its support for al-Shabab. They are consistently recruiting for them, but also doing their bidding in Kenya. So there are indications of lone wolves and terrorists and al-Shabab members across the country. But it is difficult separating people who are acting in the interest of marginalization from those who are actually declared members of al-Shabab. For instance, we know that along the coast there is the Mombasa Republican Council, who are for separatism but seem to share a bit of sympathy with al-Shabab at the level of certain individuals. This is not necessarily the position of the group. There is much interaction of this kind. That makes it difficult for one to clearly assess exactly how many young people could be declared sympathizers of al-Shabab.

How well-informed are Kenya's intelligence services about the intentions and capabilities of al-Shabab?

What we have seen so far is that after the Westgate attack, the security agencies said they had given a warning, that they had intelligence to that effect. And there are certain rumors in Kenya that even in this particular case, they have also given the same indication. What we are not so sure about is the level of precision of intelligence gathering and whether or not what is sometimes communicated to the security agencies has to do more with very broad indications of what is going to happen. With such sporadic acts as al-Shabab carries out, sometimes it's quite difficult for the security agencies to infiltrate some of the operations, track them in real time and succeed in preventing them.

Andrews Atta-Asamoah is a senior researcher in the Conflict Prevention and Risk Analysis Division at the Institute for Security Studies in Pretoria.

Interview: Mark Caldwell