The death toll of twin attacks on Saturday night in Hindi and in Tana Delta has risen to 20.
In Hindi, Lamu county, police found 11 bodies scattered in farms.
The Nation crew of reporter Galgalo Bocha and photographer Kevin Ondit have confirmed the count.
Eyewitnesses say the attackers were young men dressed in jungle-wear uniforms. They carried machetes and guns and spoke mainly in Somali language.
The victims, 10 men and one boy, were either hacked to death or shot dead by the attackers in Malamandi, in Hindi division of Lamu West.
Separately, heavily armed attackers invaded Gamba police station, in Garsen, Tana Delta county, killing nine people on the spot including a police officer on duty and inmates.
The attackers also released a suspected ringleader of the recent Mpeketoni attacks who was being held in the police station.
According to AFP, a spokesman for Somalia's Al-Shabaab group issued a statement claiming that their fighters had carried out another attack in the area.
"The attackers came back home safely to their base," Al-Shabaab military spokesman Abdulaziz Abu Musab said, claiming that 10 people had been killed in the attack.
Confirming the incident, the Deputy County Commissioner Mr Mike Kimoko said the attackers killed the policeman on duty, before pulling out five people held in police cells and shooting them to death.
They further pulled out other three civilians in a lorry which had just arrived at the police station and killed them before disappearing into the bush.
“Gunmen with strong power attacked the cell at around 11 o'clock and killed a policeman, five prisoners and three other civilians who had just arrived at the police station,” confirmed Mr Kimoko.
He explained that the policeman who was taking charge of the cell was killed during the exchange of fire between the security officers and the attackers before they broke into the cell.
He said the attackers took advantage of the darkness in the police station, which is not connected to electricity, and it was hard to tell the total number of the attackers