Somalia-based rag-tag militia Al-Shaabab on Tuesday evening staged an attack on Dadajabula Police Station in Wajir, some 683 kilometres from the capital Nairobi.
A local administrator told the Nation that the gunmen attacked the station located 13 kilometres from the Somalia border with heavy artillery, including rocket-propelled grenades (RPGs).
The government official, who sought anonymity because he is not authorised to issue media statements, said the attackers stormed the station after two members of the terrorist group were arrested and locked up.
A police source said the station was holding two terror suspects and they suspect the attackers were on a rescue mission.
"The attack was about rescuing two Al-Shabaab suspects we were holding at the station," he said.
A police brief sent to Vigilance House, the police headquarters in Nairobi, and seen by the Nation says the attackers, who were chanting in Somali, struck at 8pm as it rained heavily.
"It was dark and the officers dispersed in different directions from the camp and exchange of fire ensued," the statement reads in part.
Locals say heavy gunfire rent the air for more than 20 minutes as the officers and Kenya Defence Forces attempted to stop the gunmen.
"Heavy gunfire reported in Dadajabula, Wajir South... heavy barrage of artillery and RPGs reportedly being fired as security forces including the military battle with attackers," Ali Awdoll tweeted.
When the guns fell silent, the two suspects were lifeless, and left two police officers and a reservist were nursing injuries.
According a follow-up brief sent to Vigilance on Wednesday morning, one of of the police officers was shot in the hip, with the bullet exiting, while the other has a bullet lodged in his stomach.
An unidentified civilian, a woman, also suffered gunshot wound and police say her condition was unknown by Wednesday morning.
"Now being attended at Dadajabula Dispensary. They need further specialised treatment and arrangements being made," the brief reads in part.
However, it was not immediately clear if the suspects were felled by bullets fired by the Shabaabs or Kenya Defence Forces.
"We suspect the attackers killed the suspect in custody to conceal some information about Al-Shabaab," said the police source.
The Kenyan military has launched a major operation to trace the attackers as the bodies of dead suspects were removed to Dispensary for identification and autopsy.
"All the 16 officers have been accounted for... All arms are intact," local police chiefs told Vigilance House.