Two people died on Monday after suspected Al-Shabaab militants attacked a convoy of two buses and a police vehicle in Mandera County.
The incident happened as both County Commissioner Onesmus Kyatha and County Police Commander George Seda headed to Garissa for a security meeting.
County head of criminal investigations, Benedict Kigen, said the militants laid an ambush between Olla and Sarman villages on Mandera-Rhamu- Banisa road in Mandera North Sub-county.
The two buses heading to Nairobi from Mandera were being escorted by security officers from sub-county police headquarters.
On Sunday, one of the buses and police officers were forced to abort a trip as they neared Sarman after they were shot at.
"We have reports that one of the buses and police spent the night at Olla after they returned from Sarman on Sunday. They were shot at but successfully managed to make a U-turn," Mr Kigen said.
On Monday morning, another bus from Mandera joined the group that spent the night at Olla, only to be ambushed as they drove into Sarman village.
Mr Kigen said more casualties were likely as official communication had not yet been sent.
"A terror incident was reported at about 1pm but up to now I am yet to get the full details of what happened there," he said, blaming poor communication networks for the delay.
A source at Banisa Sub-county Hospital said the facility received two injured police officers.
Mr Kigen said police officers from all the relevant security agencies were deployed to the scene.
He said, however, that they were being cautious, fearing the attackers may have planted explosives there.
It emerged later on Monday that the attackers could have been in the area for the past one week and that security apparatus were aware but did not take action.
Mr Kigen said reported sightings of Al-Shabaab militants are of one or two individuals, who are difficult to trace and arrest.