These articles say this is actually a campaign that has been going on since December by al-Shabab because Kenyan troops have entered Somalia, Related:
Kenya police say arrest three trying to enter British army camp
AFP
Kenyan police have arrested three men who tried to force their way into a British military camp in central Kenya, according to an internal police report seen by AFP Monday.
The men were arrested at 5pm on Sunday, just hours after Al-Shabaab Islamists stormed onto a US-Kenyan military base in the coastal Lamu region, near the border with Somalia, killing three Americans.
The report said officers "managed to arrest three terrorist suspects who had earlier in the day tried to force their way into British Army Camp but in vain."
Read more at: https://www.msn.com/en-us/news/world/kenya-police-say-arrest-three-trying-to-enter-british-army-camp/ar-BBYFuH5