At least one passenger was killed at 10 others wounded when gunmen ambushed two buses between Olla and Sarman, Mandera county, on Monday.
The buses were headed for Mandera town in the morning when gunmen believed to be al Shabaab militants sprayed them with bullets.
Witnesses said one of the buses overturned as the driver sped off from the scene of the attack seriously injuring some of the passengers.
The witness said the gunmen wanted the buses to stop, which could have caused several deaths.
There were no police escorts at the time of the incident.
“We have many casualties but so far 11 have been brought to a local hospital after the incident. They have multiple injuries,” said a senior police officer aware of the incident.
The buses usually leave as a convoy as part of efforts to address security.
The area of the attack, which is the northern part of the county has been a safe area since 2013 but has lately been a soft target.
This is the latest incident to happen in the area in a series that are staged by al Shabaab gunmen.
Governor Ali Roba had protested the trend of the incidents, saying they had crippled the area’s economy.
Northeastern regional police boss Rono Bunei said the gang escaped to a nearby thicket and that teams of security agents had arrived there.
“We are pursuing them towards the Somalia-Kenya border where they escaped. They will be caught,” he said.
Last month, the gang also tried to attack a communication mast in Afaat, Wajir county, but three of them were killed. It emerged one of them had worked in the area as a mechanic for a while before he vanished to Somalia to join the militants.
Police have been mounting operations in the area to deter their plans.
The terrorists have been targeting security installations in the area in a series of incidents destroying them.
This has affected, among others, the education sector, forcing tens of teachers who are non-locals to flee.
The border region has borne the brunt of repeated attacks from the militants who are at times aided by locals.
The area is near the Somalia border and the militants usually cross at will and stage attacks before escaping back.
Al Shabaab insurgents have been attacking places in the region especially in Mandera and Garissa after breaching security zones, which left dozens of civilians and security officials dead or wounded.
They have been planting explosives on the routes used by the security agencies and attacking them.